The Back to Karkand expansion for Battlefield 3 will be released sometime in December, and will feature four new maps:
Strike at Karkand, Gulf of Oman, Sharqi Peninsula and Wake Island (a snippet from the concept art for the new Wake Island map is shown in my  header logo).

Three (3) new vehicles will also make an appearance, in the form of the Desert Patrol Vehicle (or DPV), the BTR-90 (Russian 8×8 wheeled armored personell carrier), and the F35 STOVL Jet Fighter.

Back to Karkand also brings back ten (10) iconic weapons from the Battlefield series, five new dog tags, fire new achievemens/trophies, and a new “persistence reward system” that rewards points for completing certain assignments.

Pricing will be US $15 or €15 for those who didn’t preorder Battlefield 3: Limited Edition, but will be free for everyone who did.