SOCOM 4 multiplayer early access beta codes will be granted to those who purchase Killzone 3. Killzone 3 will be released exclusively for the PS3 on February 22. SOCOM 4 will have 32-player multiplayer matches and if you want in on the action before anyone else you have to buy "specially marked" copies of Killzone 3. Make sure to keep an eye out for SOCOM 4 stickers on applicable copies of the game.
A launch date for the SOCOM 4 beta has not been announced but Zipper Interactive's Chris Roper assures gamers more information will be announced soon.
"To get early access to the beta, look for the SOCOM 4 callout on the front of all eligible copies of Killzone 3 (including both the standalone and Helghast Editions). Inside the box you’ll find a PSN code that you’ll be able to redeem for your early access as soon as the beta goes live. To find out when the SOCOM 4 multiplayer beta begins, be sure to check back at SOCOM.com once you pick up your copy of Killzone 3, hitting shelves on February 22nd."
Source: PlayStation Blog