Both Greenpoison and Limerain are based on Geohot’s Limera1n exploit and both can jailbreak Apple TV 2. But it is the first time p0sixninja posted an image of jailbroken Apple TV with Greenpoison.
We can also see an option to inject/install third party apps on Apple TV with Greenpoison and it shows we are one step away when we will be installing Apple TV apps from Cydia.
There is no ETA available for this version of Greenpoison which supports Apple TV 2 Jailbreak, but we can expect this new feature in upcoming Greenpoison RC 5 which will bring iPhone 3G Jailbreak support.