Many thanks to the efforts of the iPhone Dev Team, you will be able to install apps on your AppleTV. An upcoming Jailbreak tool, called SHAtter, has already been used to unlock the new Apple TV’s firmware.
SHAtter was used to jailbreak the newest iPod Touch shortly after its launch, and thanks to its iOS roots, the AppleTV is also susceptible to its power. The hack was carried out on the firmware restore download just been posted by Apple. This file, which contains the entire OS of the Apple TV, is an IPSW file, the file-extension for iPhone and iPad OS files.
According to the Dev Team member Will Strafach, “the new AppleTV OS seems to be a mashup of the old AppleTV OS and iOS.”
With a jailbroken AppleTV you should be able to run anything that will run on the iPad.
A final word from Strafach: “The most interesting thing about the new AppleTV OS is that all binaries are marked iPad-compatible. I do wonder what Apple is planning…”