Use your search function... http://community.callofduty.com/thread/200424928?tstart=0
Is one of many threads. There is no information released on this, and probably will not be until the MP reveal or later.
Reading is a wonderful thing. If.. you...preorder.... YOU GET NUKETOWN 2025. All you have to do is ask the dealer if they are participating in the promotion, and it sounds like they are.
Most dealers will upgrade the Pre-Order if you ask once they are announced.