In a response to the question “will their be any DLC for MW2 anytime soon” one of the developers responded:
DLC is planned for the wonderfully vague timeframe of Spring. I’ll let you know when we know when it’ll be done.
This really does not come as a surprise since Call of Duty 4: Modern Warfare and Call of Duty World at War both had multiple map packs. What is a surprise is we won’t be seeing it until sometime this Spring. As we get word of a more solid release date we will be sure to bring it to you.