http://www.cocoacontrols.com/controls
http://code4app.com/
http://www.raywenderlich.com/14742/core-data-on-ios-5-tutorial-how-to-work-with-relations-and-predicates
论坛：
http://www.cocoachina.com
http://www.devdiv.com/ios_iphone_-forum-111-1.html
http://www.cnblogs.com/cate/ios/