This is the website of Cocos2d: http://www.cocos2d-iphone.org/
Download: http://www.cocos2d-iphone.org/download
Okay, I am trying to make an iphone version of a game I made here http://scratch.mit.edu/projects/techy/781198 is box2d or Chipmunk is better, where is each tutorial
If you download the Cocos2d SDK, there are examples of Box2d and Chipmunk in the attached project. Just open the Xcode project named “cocos2d-iphone” and check out Box2dtest and Chipmunkdemo. Box2d is more powerful, but I find it more difficult to use than Chipmunk.
This is the website of Cocos2d: http://www.cocos2d-iphone.org/
Download: http://www.cocos2d-iphone.org/download