The title says it all really. It's coming out for Wii, PS2, and PSP!
Kliff and Justice are back, a new story mode is in (Hell Yeah!), and 3 on 3 Fighting! (More Hell Yeah!)
Full info/Press Release here: http://www.aksysgames.com/2009/01/27/hear-ye-hear-ye-guilty-gear-xx-accent-core-plus-in-the-house/
I personally love the Guilty Gear series, and now the best version of XX is being released in the States! With this and Devil Summoner, today has been a good day for game releases.