Golem.com reports that Apple will launch a new AppleTV box, internally numbered 3.2. Based on the FCC documents, the next AppleTV will have an edge length of 93.78mm - the previous model measures 99mm. In addition, the performance is supposed to increase: instead of the previous single-core SoC A5, the dual-core A5X will probably be used, which also works in iPad 3. This would at least provide enough power for Full-HD streaming (which the current AppleTV box already does, though).
But the most popular is still the second AppleTV generation or the first version, which comes in black: only here a jailbreak is possible. For AppleTV 3 no corresponding tool has been released yet - so you have to rely on iTunes and cannot stream media via DLNA. This is possible with an AppleTV 2 and a FreeNAS with minidlna possible without any problems - but only up to videos in 720p, 1080p the small black one unfortunately cannot display. Whether there will be a jailbreak for the upcoming new version of Apple's TV-Box is still open.