The Dev Team/GreenPois0n vs. geohot/limera1n jailbreaking dustup took an interesting turn when George Hotz himself boasted that his exploit would also jailbreak the new Apple TV 2G's. From the official limera1n site:
"Apple TV is technically supported, but there's no apps yet"
Erica Sadun from TUAW has confirmed she was able to use limera1n to get her Apple TV into administrator mode. However, with no ATV apps available, for now it's an academic exercise at best.