XBMC Comes to Apple TV 2, iPad and iPhone
The XBMC team have announced an ARM-based release of their open source media player and entertainment hub for the Aple TV 2, iPad and iPhone. The software, that requires a jailbroken device, allows users to stream and play any audio and video format from local network stores. Your Apple TV also retains its normal functionality, and you can still watch/purchase content off iTunes.
XMBC is a great piece of software, and I have it installed on my original Apple TV streaming media from my 2TB ReadyNAS NV+.