You can get access by pre-ordering the game, or can wait for the Open Beta shortly afterwards.
As part of the Call of Duty League Championship Weekend that concluded yesterday, Activision and Infinity Ward finally lifted the curtain on the plan for Call of Duty: Modern Warfare II’s betas.
Starting with an Early Access Beta available exclusively on PlayStation consoles to those who pre-ordered the game between September 16-17, this will be followed up with an Open Beta available to all PlayStation users from September 18-20.
As for where Xbox and PC players stand, the Early Access Beta for these platforms is set for September 22-23, which will also be the same dates for yet another PlayStation Open Beta, and then after this, all three platforms will get an Open Beta between September 24-26.
This is all ahead of Call of Duty: Modern Warfare II launching on PC, PlayStation and Xbox on October 28.