It only makes sense: the AirPlay video streaming features of iOS 4.2 on the iPad are all well and good, but there's no way to use them effectively if the Apple TV doesn't get a version bump along with the mobile devices. Sure enough, AppleInsider notes that 4.1 for the Apple TV should be coming along about the same time as 4.2 drops.
Besides the video and audio streaming capability, the update is also going to add VoiceOver accessibility to the iOS-based Apple TV. Macworld sa