Preview at WWDC likely in June, followed by September launch.
Brightcove Makes it Easier to Develop Dual-Screen iOS and Apple TV Apps
The new solution enables media publishers to develop rich content apps for the iPhone and iPad that simultaneously control content, data and information presented on an HDTV while displaying synchronized content on the iPad or iPhone. The unique dual-screen solution leverages Apple's AirPlay technology, which allows viewers to use applications that simultaneously present content, interactive options and data on both the touch device and an Apple TV.This ability to broadcast separate content to a user's device and Apple TV is not new (Real Racing 2 HD Demo), but the new APIs provide another easy way for developers to implement these features. Brightcove offers this demo of how it can be used:
There's been a lot of attention to how Apps might work on a television interface. Microsoft recently announced a new technology called SmartGlass which offers a two-way Airplay-like standard that allows mobile devices to act as second screens for content being displayed on TV from an Xbox.
Beyond Apple's own efforts with AirPlay, there has been rumors that Apple might take it a step further with a fully developed Apple TV app model as well as the possibility of a full Apple television set in the near future.