Ok! Linked below is the library you will need to add AppleTV IR input to your iOS app; the mapped keys are in the header file. Basically what this should do is send the remoteButton* events to your first responder. It's up to you to figure out how to react to them. Remember, these are your only input.
N.B. Do not attempt to submit an app to the App Store with this included. Not only might that get you rejected but this library will potentially change a lot before the AppleTV hack is ready for release.
You'll have to call the +sharedInstance method once before you receive events. Other than that, couldn't be simpler!
As soon as you think you have something working let me know, and send me your debug build and I'll see if it all works on our AppleTV hack. Design your app for 720p (you can run 720p apps in the iOS Simulator with a little setScreen:-ing on UIWindow after you turn on the TV out simulator).
I can't yet give out anything else related to the AppleTV iOS App SDK, but this is enough to give you a head start, and let you start thinking about TV-specific apps. I understand that you won't be able to test and debug these directly, but if you're really going to attempt this then I can't imagine that will stop you.