These are my thoughts on Wu Kong right now. This is more of a build than a guide, as I am not an expert on Wu Kong.

Pros:
Can absorb some damage
GREAT early ganking
Easy to escape if played well

Cons:
Weak midgame as you farm the trinity force
Lackluster team fight performance
Is not a Warwick in the jungle... takes some practice to jungle him well
No overextended lanes leads to an underfarmed Wu Kong

Madred's Razors - necessary to jungle early game. Your damage to minions will suck without it

Wriggle's Lantern - Lifesteal and more frequent Madred's passive. A great jungling item for Wu Kong

Boots of Mobility - When you are moving between lanes, it pays to be in their lane before they think you are. It also synergizes well with your decoy. These boots can help you get more distance between you and the enemy after your decoy. It also helps Wu Kong enter lanes stealthed quickly enough to burst down a champion at low health. Once team fights begin, trade these for mercury treads.

Trinity Force - Welcome to DPS. Once this is built you get a great amount of damage. Build each part as you think you need them. If enemies are escaping, build your phage first. If you aren't fast enoughor dont have enough sustained damage, build zeal first. If you need more burst damage, get the sheen first. This item is really a must on Wu Kong.

Banshee's Veil - You don't have a whole lot of MR as Wu Kong. This will push you just over 100 MR, gives you health and mana, and its passive is great. Even if you prefer a higher DPS Wu Kong, this makes him a great threat to squishy mages.

Atma's Impaler - This can usually be built by the 30 minute mark if you are ganking effectively. While it is expensive for what it does, this build focuses on the Atma/Warmog combo. If you don't like it, use the other build.

Warmog's Armor - This gives you that extra beefiness. By the time you buy it you will have over 2.5k health and 100 MR 150 armor. This gives you some good damage with Atma's and makes you harder to kill.

Force of Nature - I build this item last, if the game isn't over, to replace Wriggle's Lantern. With all the health you built, this pushes your MR over your armor and makes every enemy AP carry want to kill you before you can get to them.

Just a word about how this build works. Wu Kong plays as an assassin, you single out a target, get to them with your e, lower their armor with q, and then decoy until you can repeat.

Jungle:
Start at banshees smite the blue one, and nimbus to the 3 small ones, beat em down
Proceed to wolf camp, nimbus the big one and finish killing them. This will get you level 2.
Go to Dual Golems, your smite should be off CD now. Nimbus one, hit an auto attack, q, then a second auto attack followed by smite to finish off first one. Kill 2nd golem and check for a gank.

GANK TIME. You have high burst DPS that ganks well with a high dps solo champ that will benefit from your armor lowering q. If the lane you are closest to is overextended, ask the people in that lane if they want to gank.

If you successfully gank, you will have enough for Madred's Razors (and possibly boots if fb) Go b and get these items. If the gank was unsuccessful, farm either the lane or jungle until you can get them.

After Razors, the jungle is yours. Start at blue and clear the whole thing, spamming e and q as they come off CD.

At level 5, you gain a new option to enter lanes in stealth. DO NOT USE W TO ENTER A LANE UNLESS YOU ARE SURE YOU CAN ESCAPE WITHOUT IT. This means that you only use that w to enter a lane if the enemy champion(s) are low enough to burst down and chase without a slow. If this is not the case, as it usually isn't, save your w for after your initial e/q burst.

Things I have noticed:
Saving your ult until after you decoy and get the majority of the enemy team near you. This will knock them up before they can CC you and allows you to put out some decent AOE DPS. Usually If you wait until then, they won't bother CCing you as you can't knock them into the air anymore. That is their mistake, you put out enough DPS to really cause a problem.

There is more to come! Will make some Wu Kong lane builds too and change the name of my guide when i get tired of jungling him. Constructive Criticism please. I would love to try out some of your ideas.