Cocos2d - Wikipedia (Looks very outdated!)

http://en.wikipedia.org/wiki/Cocos2d

Book that Ray is in the process of writing........

http://cocos2dbook.com/

Performance Tips for the cocos2D on iPhone

http://allseeing-i.com/Performance-tips-for-Cocos2d-for-iPhone

Moncle Studio's site - Quite outdated!

http://monoclestudios.com/cocos2d_whitepaper.html

RAYWENDERLICH's site that has very nice tutorials for iPhone

http://www.raywenderlich.com/352/how-to-make-a-simple-iphone-game-with-cocos2d-tutorial

cocos2d - Tutorial

http://www.bit-101.com/blog/?p=2138

Stephen's Main Site

http://www.learn-cocos2d.com/

I believe there is no better site than this to learn COCOS2D. Coupled with his book - you can easily master COCOS2D in record time.