ios game center tutorial

网上找到两篇很好的ios game center入门教程，在这里分享下：

part 1 (主要是iTunes connect里面怎么样设置app) : 

http://mobile.tutsplus.com/tutorials/iphone/ios-sdk-game-center-achievements-and-leaderboards-part-1/

part 2 (主要是编写代码实现Achievement和Leaderboards的操作) :

http://mobile.tutsplus.com/tutorials/iphone/ios-sdk-game-center-achievements-and-leaderboards-part-2/