The PS3 version of this game is region-free, because the console itself is region-free. Not only that, but a lot of 360 games are actually region free as well, although I don't think we know if this particular one falls into that category just yet.
If you really want a region-free 360 version, I suggest checking sites like Play-Asia.com. The Asian versions of most 360 games are not only region-free, but completely in English.
I didn't noticed that this forum is visible both for PS3 and X360 version. I want region free X360 version. I live in Europe but my friends are in the USA all the time so they can get me the game. I know that most X360 games are region free but because this one is released only in USA and then after three months from now everywhere else I'm suspicious that it could be locked. I know about Play Asia but they still don't have information about region lock. But anyway, thanks for answer.
I bought the game from the USA (NTSC edition) and I can confirm that it's region free and works without any problem on my "PAL" X360. Even download of Year one movie is ok as included DLCs on the second disk.