Apple TV Updated to version 5.0
Along with the iOS 5.1 updates for the iPhone and iPad, Apple have also updated the existing Apple TV’s to version 5.0.
This update brings all the new features mentioned for the new Apple TV announced tonight (but without the 1080p playback).
You an update directly from the Apple TV.
And Firecore are advising you to steer clear of the update if you want to jailbreak.