This is the new (black) AppleTV software being tested on an iPhone with some aTV Flash components installed.

This is the new (black) AppleTV software being tested on an iPhone with some aTV Flash components installed.

so this is using the limera1n exploit i assume
As was stated in their blog post, aTVFlash Black will require a pre-existing Jailbreak, and they will simply be providing the applications to enhance the experience.
Of note, I would personally recommend going with PwnageTool rather than Limera1n at this point, as currently PwnageTool is the only one that will actually pre-install SSH for you so that you can get in to add additional packages at this time.
The other tools will jailbreak the AppleTV, but leave you without a means of installing additional packages (like Cydia, which is currently non-working, ssh or other working command line applications). While that will certainly be fixed soon, the other tools (Greenpois0n and Limera1n) are currently non-useful in their current state.