Map Pack 3 has recently been released for PS3 and Xbox 360.
Again the DLC has no release ETA at this point in time for PC, but in the meantime here are 3 new MP maps and Zombie map to salivate over while you wait for the release.
The maps are, in order
Breach - Berlin's crowed city streets
Battery - An armored island in the Philippines
Revolution - A Russian city in a factory environment
Der Riese (zombie factory) - new zombie map