Physical Editions of Call of Duty: Modern Warfare II can be pre-ordered for PlayStation and Xbox consoles. All Physical Editions on consoles include Early Access to the Call of Duty: Modern Warfare II Open Beta* when pre-ordered at participating retailers.
However, if you pre-ordered the game digitally on the Xbox or PlayStation digital stores, or on Battle or Steam on PC, you can get access to the Campaign early. You can already pre-load the Campaign just now (it should already be in your game library), so you can start playing as soon as it goes live.