Killzone 2, it appears that upcoming Guerrilla Games FPS Killzone 3 will be getting a beta in some form. A recently launched site with the URL "http://beta.killzone.com/kz3/beta-login.html" and a gated login (that's apparently not allowing anyone in as of right now) certainly seems to imply as much. Adding to the possibility is the fact that the Killzone 2 Community Website service on PSN lists "Killzone 3 Beta Website" as a launchable location, as spotted by Iron Star Movement.
We've reached out to Sony and Guerrilla for more details, but we have to imagine it won't be completely different from betas we've seen in the past-- (say, the Killzone 2 beta, for instance -- with online multi and a few game modes, perhaps). That said, this game does have jetpacks, and that changes things a bit -- namely, our excitement for more info.
Update: Sony responded, saying, "Guerrilla Games is currently testing a number of elements internally with Killzone 3 and further details will be available soon."
[Thanks to everyone who sent this in!]