如何实现iTunes内置App“文件共享”功能

I've noticed that several apps, when an iP* is connected, has a "File Sharing" feature inside of iTunes. Example applications are CloudReaders, Stanza, etc. This interface lets users Add files to the app and Save files from the app to their computers. Right now I've got a HTTP server running inside the app which lets users add files to it via Wi-Fi, but I'd like to support the aforementioned method as well.I've noticed that several apps, when an iP* is