Adonass' Zilean

First off my Zilean play style is Very Aggressive
Your runes are set to be a early killer
Your items vary after the first 3
The skills are quite self explanatory, Time Bombs kill and Rewinds make more bombs!
Your summoner spells are to change the way you build ur items early on.

Reasoning
Ill Skip to Items because its very important you know how to recognize what to buy in order to insure a smooth game with Zilean.

The first 3 items are chosen to change zilean from a minor dmg support, into an early game fear
Rabadons + clarity + mana pots makes a true power house zilean.
with this item setup you are able to feed on creeps while pushing champions back to where they cannot gain exp!
Now depending on your game and play style you can follow up rabadons with a mejas or continue to follow my build.
Mejas is a great choice especially if you were fed early on other wise id keep it safe and leave it out :)

-Mejas if you are noticing kills and assist everywhere!

-Rod of Ages, why because, end game u want to time warp across the map without feeding on mana pots the entire game..

Now your boots can be made at any time i usualy find a time while making one of the first 4 items above.

Your last item is just to top off all that dmg output. If you want survivability go with Rylai's Crystal Scepter.

Play Tips
Work with your partner! you guys can chase down low enemies, you have Time Warp and Chrno Shift but care for mias..

Chrono Shift opens up opportunities to juke, towerdive and be reckless dont forget it..

And finally bombing, you could bomb the hell out of your enemies or you could (when dealing with mele enemies, Bomb, Rewind, Bomb the creature they are attacking, you'll see a tremendous burst on the hero and also receive gold for nearby creeps!

Well GoodLuck and dont die! =D