I built CCCPushManager as a way to send push notifications for my new app Letters - a game about spelling words. Please check it out!
A client reference implementation for PushServer demonstrating how to register/update a device token, subscribe to channels, unsubscribe from channels, and retrieve the currently subscribed channel list.
This example uses AFNetworking internally to talk to the PushServer. The example code is not a standalone working class (although it could be if you have the right AFNetworking library in your app), it is more illustrative of how one might interact with the PushServer backend.