Multiplayer maps Liberation, Piazza, Overwatch and Black Box.
Spec Ops missions Black Ice and Negotiator.
Price, unknown, but probably $15-$20.
Also, the DLC calendar has been updated again and includes 22 pieces of content. The month of May originally had a MP map and a Spec Ops mission. Then a "Classified" item was added a month ago or so, and now another "Classified" item has been added to May again.
UPDATE (Mar 12):
A preview video for the collection was just released.
This map pack will likely be available "on or around" April 19th for PS3.