So, first, let's go between the differences between them.
Walling: A play style where Pokemon are trained to be able to endure physical, special, or both types of attacks and used to outlast the opponent.
Stalling: A play style used in which damage is usually incurred indirectly through status moves, entry hazards, or other moves.
Support: A play style where moves are used to support the team in general, not just the Pokemon in play.
Note that tanks are a combination of walling/stalling and damage.
   
Methods of Walls/Stallers/Support:
In stalling/walling, damage is usually through indirect effects such as Hail, Sandstorm, or status. Entry hazards such as Spikes and Stealth Rock are also often taken advantage of.
Walls and Stallers are generally used to outlast the opponent rather than beat them into submission.
Support Pokemon are used in several different roles. They usually use, but are not limited to:
-Baton Pass roles.
-Setup.
-Entry Hazards.
-Healing of other Pokemon.
-Disruption.
-Forcing switches.

Stats:
Base stats are important for setting up walls. For example, a Ninjask would make a terrible wall due to its low defense and special defense stats. The specific stat is also important; a Blissey, with its huge 130 Sp. Defense, makes an excellent wall against Pokemon like Alakazam, whose main power lies in its Sp. Attack, but its paltry base 10 defense makes it vulnerable to anything with a physical attack.
In addition, HP is a very important factor. Sometimes, to combo with Flail, Reversal, or Endeavor, the HP must be indivisible by 4. Most of the time, though, it's generally recommended to run as high HP as possible, as it serves the purpose of both defending stats at once.

Setting up Walls/Stallers:
Sometimes, setting up walls is as easy as sending in, say, a Skarmory against a physical Salamence.
Other times, it can work similarly, except that special moves are used to boost its defensive capabilities.
These moves usually boost defense in some sort, or recover HP to allow more setup. The main moves to keep in mind are the ones that boost by 2 stages or Stockpile and Cosmic Power, as these are great to help set up. Note that these are not all the stat-boosting moves, nor is it completely made of stat-boosting moves. Moves like Ingrain and Leech Seed help to set up as well. Also, moves that boost both a defensive stat AND an offensive stat are better suited for tanks than for walls/stallers. Some, such as Confuse Ray, are used by walls because they're often a wall's method of offense, as they oftentimes lack strong offensive stats.

In addition, Substitute is a wall/staller/support Pokemon's most useful tool. For the cost of 1/4 of its HP, it creates a decoy that resists all status moves and can take damage for the Pokemon. This 1/4 HP cost is usually healed off through various effects.

Moves used on Walls/Stallers:
Many of these moves cross over into Support, especially if the support Pokemon has Baton Pass.
Acid Armor: Defense, 2 stages.
Acupressure: Random stat, 2 stages.
Amnesia: Sp. Defense, 2 stages.
Aqua Ring: Recovers HP every turn. May be Baton Passed.*
Attract: Makes the opponent infatuated.*
Barrier: Defense, 2 stages.
Bulk Up: Attack and Defense.
Calm Mind: Sp. Attack and Sp. Defense.
Charge: Sp. Defense.
Confuse Ray: Inflicts confusion.*
Cosmic Power: Defense and Sp. Defense.
Curse: For non-ghost tanks. Attack and Defense, but lowers speed.
Defend Order: Defense and Sp. Defense (exclusive to Vespiquen).
Defense Curl: Defense. Can be combined with Rollout or Ice Ball.
Destiny Bond: If user faints, opponent also faints. Used as a last sacrifice when the wall can no longer function.
Detect: Negates all attacks directed at user. May fail if used consecutively.
Double Team: Evasiveness.
Explosion: Used by a wall/staller when they can’t go on any further, to take another Pokemon down with them.*
Flatter: Boosts enemy's Sp. Attack 2 levels, but confuses the enemy. Not recommended.
Follow Me: Only useful in double battles; makes all enemies attack you. Useful when you need to protect your other Pokemon.*
Glare: Paralyzes opponent.*
Grasswhistle: Puts opponent to sleep.*
Hail: Mainly for stallers. Deals DoT to all non-Ice types without Magic Guard.*
Harden: Defense.
Heal Order: Heals 1/2 HP. Available only on Vespiquen.
Hypnosis: Puts opponent to sleep.*
Ingrain: Heals HP over time, prevents switching out or being forced to switch out.
Iron Defense: Defense, 2 stages.
Leech Seed: Drains opponent's HP over time, heals self's HP over time. Will transfer to next Pokemon if you switch out.*
Lovely Kiss: Puts opponent to sleep.*
Magic Coat: Reflects non-attacking moves directed at user back to opponent, i.e. Toxic, Leech Seed.
Milk Drink: Heals 1/2 HP. Only available on Miltank.
Minimize: Evasiveness.
Moonlight: Heals HP, heals different amounts in different weathers.
Morning Sun: Heals HP, heals different amounts in different weathers.
Pain Split: Changes each Pokemon's HP to total HP between them divided by 2.
Poison Gas: Poisons enemy.*
PoisonPowder: Poisons enemy.*
Protect: Negates all attacks directed at user. May fail if used consecutively.
Recover: Heals 1/2 HP.
Recycle: Brings back used item.
Refresh: Cures Poison/Paralysis/Burn.
Rest: User sleeps for 2 turns, heals all HP and status.
Roost: Heals 1/2 HP, removes flying-type.
Sandstorm: Mainly for stallers. Deals DoT to all non-Rock, -Ground, or -Steel types without Magic Guard.*
Sing: Puts opponent to sleep.*
Slack Off: Heals 1/2 HP.
Sleep Powder: Puts opponent to sleep.*
Sleep Talk: Allows move use while asleep. Often comboed with Rest.
Softboiled: Heals 1/2 HP.
Spite: Reduces enemy's last used move's PP by 4. Can be used to force the enemy into Struggle.
Spore: Puts opponent to sleep. Has 100 accuracy and is the best sleep move in the game.*
Stockpile: Defense and Sp. Defense, can only be used 3 times. Also changes effects of Swallow and Spit Up.
Stun Spore: Paralyzes.*
Substitute: Removes 1/4 of player's HP to create a shield. Will remain if you switch out.*
Supersonic: Confuses enemy.*
Swagger: Raises enemy attack by 2, confuses enemy. Not recommended.
Swallow: Heals HP depending on amount of Stockpile.
Sweet Kiss: Confuses.*
Synthesis: Heals HP, amount varies based on weather.
Thunder Wave: Paralyzes.*
Toxic: Deals increasing Poison damage over time.*
Will-o-Wisp: Burns.*
Wish: Heals 1/2 HP on next turn. Will transfer to next Pokemon if you switch out.*
Withdraw: Defense.
Yawn: Puts opponent to sleep on next turn.*

*Can be used in Support builds.

Setting up Support:
There are a few different types of support Pokemon. Some are literally suicidal; they're meant to throw up support and either die or otherwise GTFO of the battle. Others are meant to stay in a little longer, and still others will jump out of the battle in the form of Baton Pass.
Some support IS suicide; Healing Wish, for example, faints the user but heals the next Pokemon sent in of just about everything.
There are many forms of support; most, but not necessarily all are listed above under "Methods of Walls/Stallers/Support". In fact, all the stat boosting moves in Walls and Stallers, and all of the stat-boosting moves not mentioned, can be placed under Support due to Baton Pass.
Several moves used by Support Pokemon are meant to disrupt an enemy's strategy. Encore, Roar, Whirlwind, Toxic Spikes, all are able to mess with the opponent's team, and open up opportunities for a player's other Pokemon.
The one thing they all have in common is that they’re not meant for use on their own; they’re used to prepare other Pokemon on the team.

Moves used on Support:
First, read the moves that have a star next to them in the Walls/Stallers section. Those can be viably exploited by Support Pokemon. In addition, any move that boosts stats can be used by Baton Passing Support Pokemon. Due to space, I will not include these moves in the list.
-Baton Pass: One of the best supporting moves in the game. Used to transfer stat boosts, Aqua Ring, Ingrain, Mean Look (note: Mean Look+Baton Pass is only usable on Umbreon), and more. It also has some other purposes that can stack with the above.
-Block: Prevents opponent from switching out.
-Disable: Negates the use of opponent’s last move used.
-Embargo: Prevents opponent’s use of held items.
-Encore: Forces opponent to repeat their last move used for several turns.
-Follow Me: Useful only in Double Battles. Makes opponent direct all attacks at the user. Better than it sounds.
-Foresight: Negates Ghost-type immunities to Fighting and Normal, reduces evasiveness to normal.
-Gravity: Negates Flying-type and Levitating Pokemon’s immunities to ground, boosts accuracy of moves by 67%. Also negates moves involving height.
-Grudge: When user faints, the move used to faint the user is depleted of all PP.
-Haze: Negates all stat changes.
-Heal Bell: Heals all status conditions afflicting your team.
-Heal Block: Prevents healing moves for 5 turns.
-Healing Wish: KOs user, fully heals next Pokemon sent in.
-Helping Hand: Only useful in double battles. Doubles ally’s damage.
-Light Screen: Halves opponent’s Sp. Attack damage for five turns. Remains even if Pokemon switches.
-Lucky Chant: Prevents opponent from critting. Remains even if Pokemon switches.
-Lunar Dance: KOs user, fully heals next Pokemon sent in.
-Mean Look: Prevents switching.
-Memento: KOs user, lowers enemy’s Attack/Sp. Attack by 2. Used when a Pokemon has reached the end of its usefulness to help clear the way for the next Pokemon.
-Mist: Prevents stat reduction for 5 turns.
-Mud Sport: Lowers Electricity damage. Only works while user is in battle, so it’s better in double battles.
-Perish Song: Faints all Pokemon in 3 turns unless they switch out.
-Power Swap: Switches Attack/Sp. Attack with foe. Better if user has low Attack/Sp. Attack.
-Psycho Shift: Moves status on self onto opponent.
-Rain Dance: Causes Rain.
-Reflect: Halves opponent’s Attack damage for 5 turns. Remains even if Pokemon switches.
-Roar: Forces opponent to switch.
-Safeguard: Prevents status for 5 turns.
-Spider Web: Prevents fleeing.
-Spikes: Entry hazard. First layer causes 12.5% damage to any Pokemon switching in. Each new layer adds 6.25% damage, 3 layers max. Flying-types/Pokemon with Levitate are unaffected unless under the effects of Gravity or Iron Ball.
-Stealth Rock: Effect described in: http://www.serebii.net/attackdex-dp/stealthrock.shtml
-Sunny Day: Causes strong sunlight.
-Switcheroo: Switches items.
-Taunt: Prevents opponent from using non-offensive moves, effectively shutting down opposing walls, stallers, or support Pokemon. It even passes through Substitute.
-Torment: Prevents foe from using the same move twice.
-Toxic Spikes: Entry hazard. First layer causes normal poisoning, second layer causes bad poisoning. Flying/Steel/Levitating Pokemon are unaffected. A poison-type Pokemon sent out by your opponent removes Toxic Spikes.
-Trick: Switches items.
-Trick Room: Causes slower Pokemon to move first. Does not affect priority.
-Water Sport: Halves fire-type damage. Only works while user is in battle, so it’s better in double battles.
-Whirlwind: Causes opponent to switch out.
In addition, all moves that lower the opponent’s stats can be put into this category.

Wall/Staller Items:
-Big Root: Increases amount healed from healing moves that are not normal instant healing (i.e. does not affect Recover).*
-Black Sludge: Heals 1/16 of a poison-type’s HP per turn. If not poison-type, removes 1/16 of its HP per turn. Can be tricked or used on a poison-type.*
-Brightpowder: Increases evasiveness by 10%.
-Damp Rock: Extends turns of rain to 8.
-DeepSeaScale: Only usable on Clamperl. Doubles Sp. Defense.
-Grip Claw: Extends multiple turn moves’ duration by 5 turns.
-Heat Rock: Extends turns of sunny day to 8 turns.*
-Icy Rock: Extends turns of hail to 8 turns.*
-King’s Rock: Has a chance of flinching opponent every time you use a direct attack.
-Leftovers: One of the most fundamental weapons of a waller or a staller, it recovers 1/16 HP per turn. It doesn’t sound like a lot, but with the amount of turns a waller or staller is out, it adds up.*
-Razor Fang: Has a chance of flinching opponent every time you use a direct attack.
-Smooth Rock: Increases turns of sandstorm to 8 turns.*
-Sticky Barb: Deals 1/8 damage to the user per turn. If the opponent makes physical contact, then the Sticky Barb will move over to them.
*This item can be used by Supporters too.

Support Items:
-Choice Items: Can be tricked or switcherooed.
-Flame Orb: Can be tricked or switcherooed.
-Focus Sash: Useful on suicide supporters. Lets them survive just long enough to set up support, and then die.
-Iron Ball: Again, best to switch with the opponent.
-Light Clay: Extends duration of Light Screen/Reflect to 8 turns.
-Shed Shell: Prevents trapping in a battle by moves that prevent switching.
-Toxic Orb: Switch away.

Helpful Abilities:
These abilities are often cross-build, so that you can use them in Support, Walling, OR Stalling. Experiment with them to find their full potential.
Also, Abilities are not yet programmed into PokemonCraft, so this is more for competitive battling.
Now, into their categories:
Healing and Healing over Time:
Gluttony: Causes quicker consumption of berries.
Hydration: Cures status during Rain. Can be comboed with Rest.
Ice Body: Heals 1/16 HP during Hail.
Leaf Guard: Prevents status during Sun.
Natural Cure: Cures status upon switching.
Poison Heal: Heals 1/8 HP per turn if poisoned. Poison's effect is ignored.
Rain Dish: Heals 1/16 HP per turn under rain.
Shed Skin: 30% chance per turn of curing status.
Volt Absorb: Heals when attacked by electric attacks.
Water Absorb: Heals when attacked by water attacks.

Anti-Contact:
Cute Charm: 30% chance of causing infatuation if opponent makes contact. Not recommended.
Effect Spore: 10% chance of causing Sleep, Paralyze, or Poison when foe makes direct contact.
Flame Body: 30% chance of causing burn when foe makes physical contact.
Poison Point: 30% chance of poisoning foe if they make physical contact.
Static: 30% chance of paralysis if foe makes direct contact.

Damage Negation:
Overlaps with Volt Absorb, Water Absorb, and Dry Skin.
Filter: Quarters super-effective hit damage.
Flash Fire: Negates Fire-type attack damage, increases Fire-type move power by x1.5 if hit by Fire-type move.
Heatproof: Halves Fire-type damage.
Levitate: Negates Ground-type damage.
Magic Guard: Prevents damage from indirect attacks, such as Sandstorm.
Solid Rock: Reduces super-effective attack power by 33%.
Soundproof: Negates sound-based moves.
Sturdy: Prevents OHKO moves.
Thick Fat: Halves Fire and Ice type move damage.
Wonder Guard: Prevents damage from non-super-effective moves.

Attack/Effect Negation:
Air Lock: Negates weather effects; does not negate weather. Only available on Rayquaza.
Clear Body: Prevents stat reduction.
Cloud Nine: Negates weather effects; does not negate weather.
Keen Eye: Prevents accuracy reduction.
Pressure: Causes foe to use 2 PP instead of 1.
Sticky Hold: Prevents item loss, except if user gets rid of it.
Suction Cups: Prevents the effects of Whirlwind and Roar.
Unaware: Negates opponent's stat boosts.
White Smoke: Prevents stat reduction.

Status Blockers:
Technically Tangled Feet, Synchronize, and Marvel Scale do not fall under here; however, it does discourage it.
Early Bird: Halves amount of time spent asleep. Can be comboed with Rest.
Immunity: Prevents Poisoning, bad or otherwise.
Inner Focus: Prevents flinching.
Insomnia: Prevents Sleep. Does not affect Rest.
Limber: Prevents paralysis.
Magma Armor: Prevents freeze.
Marvel Scale: Increases Defense by x1.5 during status. Can be comboed with Rest.
Oblivious: Cannot be attracted.
Own Tempo: Cannot be confused.
Shield Dust: Prevents additional effects of attacks from occurring.
Synchronize: Causes burn, paralyze, or poison to foe if user is burned, paralyzed, or poisoned.
Tangled Feet: Raises evasion by 1 level when confused.
Vital Spirit: Prevents sleep.
Water Veil: Prevents burn.

Stat Boosters/Nerfers:
Overlaps with Tangled Feet and Marvel Scale.
Flower Gift: Increases self's and, if in double battle, ally's Attack and Sp. Defense by x1.5 during Sunlight.
Intimidate: Lowers Attack by 1 level.
Sand Veil: Increases evasion by 1 level under Sandstorm.
Simple: Doubles stat boosts.
Snow Cloak: Increases evasion by 1 level.

Setup:
Drizzle: Creates Rain. Only available on Kyogre.
Drought: Creates Sun. Only available on Groudon.
Sand Stream: Causes Sandstorm.
Shadow Tag: Prevents opponent from switching, even if holder switches.
Snow Warning: Causes Hail.

Trapping:
Prevents switching, which is a lot more useful than it sounds.
Arena Trap: Prevents opponent from switching while holder is in play.
Magnet Pull: Prevents Steel-types from switching out. Useful on Pokemon like Skarmory.

Situational:
Anticipation: Tells if opponent has super-effective attacks.
Battle Armor: Prevents crits.
Klutz: Prevents item use. Can be comboed with Trick, Fling, and/or Switcheroo.
Serene Grace: Doubles additional effect chance.
Shell Armor: Prevents crits.
Trace: Copies foe's ability. Can be useful if used on the right Pokemon.

Helpful Berries:
Any pinch berry that increases stats in a time of dire need is excellent for a baton passer.
Lum Berry works for its ability to heal any status condition.
Chesto Berry can work with Rest, though Lum can do that anyways.
The Super-effective attack weakening berries can also be used.
Usually, berries are less useful on Walls, Stallers, and Supporters than they are for damage dealers.

Recommended Pokemon:
Blissey-Special Wall, Healing Supporter
Bronzong-Wall, RestTalker, Screen Supporter, Weather Supporter
Gyarados-RestTalker, Switch-forcer Supporte
Hippowdon-Physical Wall, Stockpile Staller, General Staller
Skarmory-Entry Hazard Supporter, Switch-forcer Supporter, Defensive Wall
Milotic-Special Wall, Screen Supporter, RestTalk
Regice-Special Wall, Tank
Spiritomb-RestTalk, PP Drainer
Steelix-Physical Wall, Switch-forcer Supporter, Stealth Rock Supporter.
Uxie-Screener, Stealth Rock Supporter, Suicide Supporter
Umbreon-Baton Passer, Wall
Forretress-Physical Wall, Entry Hazard Supporter, Suicide Supporter
*Please note that status moves should be used as much as possible, so that I left out the build I call Status Supporter, and some builds are left out due to lack of memory and space. For example, more Pokemon, such as Steelix or the Regis, have Explosion, making them useful suicide supporters, and far more Pokemon have Stealth Rock. In addition, there is no way I could cram all possible walls in here.
In addition, many more of these Pokemon can be used as Tanks. For example, Cresselia and Slowbro with Calm Mind can become a lot harder to beat and harder to survive, and Latias' Soul Dew allows it potent Tanking capabilities.
Also, there are a lot more Pokemon that can be used as walls/stallers/supporters than just mentioned here. In fact, I edited out quite a few because there are so many.

Also note many of these moves are not yet coded into PokemonCraft. As such, make sure to check the FAQ for a list of non-working moves, and report any other combos that don't work in the Problems and Solutions forum. For now, this guide is far better for competitive battling, until all the moves are coded in.

Thanks for another sky scraper high, eyeburning post
the brave souls who dare starting to read it will surely learn much from it

Just a note, for all of you: I left some disclaimers at the bottom. If you want to read it, I suggest reading those, because they hold some critical info.
Btw, I just added abilities. Now it's even longer.
If you're only looking for PokemonCraft info, skip the abilities.

I read every single word and thanks for another skyscraper tall post giant

thanks

Whew, should've made the last edit.
Not as good as I'd like, but it'll have to do.
Stupid 20k character limit.

Hehe, thank god it has a 20k limit. xD I might never load this page. =P