Yeah thats right the Killzone 3 multiplayer beta is coming to the PSN on October 25th but there's a small process you have to go through to be eligible..
You need to be a PSN plus member in order to enjoy this becuase its limited only to them.
On October 19th an exclusive Killzone 3 theme will be available on the plus section of the Playstation store and the first 10,000 plus memeber to download this will recieve access to the public beta trial.
After downloading the theme you will recieve an email on the 25th October containing the public beta trial promotion code and further instructions through the address that you registered your PSN ID through.
So there you have it! If you're a PSN plus member then this is well worth the try.
Check it out!!