Due out in March 09, Treyarch have announced details of the adventurously titled 'Map Pack 1'.
There are to be 3 new multi-player maps and a new 4 player Zombie mission named 'Verrückt' (Zombie Asylum) which features new weapons, electro-defense systems and exciting new weapons.

The 3 new muli-player maps are 'Nightfire' set in the darkened streets of World War I Berlin; 'Kneedeep' in the pacific island jungles and 'Station' which features the underground rail system similar to that of the single & co-op campaign.

The price for the mappack has not yet been released, so keep your eyes open for further updates.