The awesome Batman: Arkham City gets its game of the year edition on Xbox and PS3 later this year - May 29th to be exact. At least, that date is good if you're in the USA, which I suspect you aren't.
Us Europeans and rest-of-the-worlders have to wait until September to get our hands on the release, which comes with all previously-available DLC and skins. It's a great game but why the extra wait for everyone outside North America? I can't really think of one. It's a bit lame to be honest. Pull your fingers out, Warners.