Apple has updated the Apple TV's software as well as the Remote app for iOS, presumably adding support for iTunes 11 and the new iCloud features introduced within it. The Apple TV release has a build number of 10A831.
The Apple TV can be updated directly on the unit by going to the Settings menu, then General, then selecting Update Software. The last Apple TV update was released back in September.
iTunes Up Next
Adds support for Up Next with iTunes 11 or iTunes Match. See upcoming songs when playing music on your Apple TV. Add new songs and edit what's queued with your Remote or with the Remote app.
Stability and performance
Includes performance and stability improvements with the iTunes Store, AirPlay, Netflix, iTunes Match, and wired Ethernet connections.
The Remote app has been updated with a new view for iPad as well, one that looks almost identical to iTunes 11. It allows users to control iTunes or the Apple TV using their iPhone, iPad or iPod touch over a Wi-Fi network.
Remote is simpler and easier with new ways to browse your library and see and edit upcoming songs with Up Next. A redesigned experience for the iPad shows all the songs in an album with the Expanded view and a more powerful search delivers results as you type.