Right now Amazon is running a deal on Call of Duty: Modern Warfare 2 where pre-orders get $20 in credit to be used towards future video game purchases. That essentially makes the price of the game $40 on all three platforms; PC, Xbox 360 and PlayStation 3.
This appears to only apply to the normal and Hardened versions of the game, but not the Prestige Edition which comes with the night vision goggles. Amazon is also offering release date delivery for the title which is free for Prime members and around $5 for everyone else.
Modern Warfare 2 will contain a 2 player online and split-screen co-op mode called Spec Ops which contains 23 unique cooperative missions. The game releases on November 10th and you can find all of our coverage on the game right here.