Battlefield 3 players on PS3 have been at the "Close Quarters" DLC for at least a week now, and Premium PS3 players even longer. It gets even more complicated: PC and 360 Premium players have been enjoying the content for some time now, too. If you're in none of these categories, today you can buy the content separately on any platform you please.
"Close Quarters" features four new maps across the new Conquest Domination and Gun Master modes, plus ye olde Team Deathmatch. There's also ten new weapons and a few other bonuses. My review of it is here. The short version: it's somewhat fun, if not exactly the Battlefield you know and love.
The DLC is priced at $15. Check the trailer below if you missed it.