常用IOS网络开发框架
AFNetworking https://github.com/AFNetworking/AFNetworking/
ASIHTTPRequest 文档: http://allseeing-i.com/ASIHTTPRequest/
下载:http://github.com/pokeb/asi-http-request/tarball/master
MKNetworkKit : 已经支持ios5
文档: http://blog.mugunthkumar.com/products/ios-framework-introducing-mknetworkkit/
下载:https://github.com/AFNetworking/AFNetworking/