Battlefield 3 fans on PC and 360 can now stop pining while watching Back to Karkand PS3 gameplay videos: the expansion has been released on your platforms too.
If we haven't beat it into your heads enough already, Karkand is a quasi-remake of Battlefield 2, and features four maps, more guns and vehicles, assignments, enhanced destruction, and Conquest Assault mode. It's free to anyone who pre-ordered or bought BF3 Limited Edition, and about 15 bucks for anyone who didn't.
360 players will also be treated to a 2gb update similar to the PC patch from last week -- expect a significantly improved gameplay experience in both single player and multiplayer. After downloading, if you need help getting into Karkand maps, see this guide. PC players require only a small update as the content was released in the aforementioned patch already.