Can I use cocos2d for iPhone in my closed-source iPhone application ?
Yes, you can. cocos2d for iPhone is licensed under the cocos2d for iPhone license. Basically it is like a LGPL license but allows you to use the library as a static library or by including the cocos2d for iPhone sources in your project. Remember that cocos2d for iPhone follows the copyleft idea. So if you improve the library, send me the patches or make them public so that I can include them in future releases.