Well, we did not see that coming. Although there's been a flurry of development around the AirPlay service for iOS 4.2 devices, iTunes and the current iOS-based Apple TV model, expectations for ever seeing the instant-play capability on the older Mac OS X-based Apple TV models was quite low. Of course, where official support is not forthcoming, enter the legions of eager hackers.
The team at FireCore (producers of the aTV Flash unlock & enhancement suite for both original and new Apple TVs) have relayed the news today that the Remote HD iPhone app (US$3