UPDATE: Sony has released more information about the free Killzone 3 multiplayer experience due out next week.
The standalone version of Killzone 3's online, released to celebrate Killzone 3's first anniversary, includes the Guerrilla Warfare, Warzone and Operations game modes, all the original Killzone 3 maps and all the Killzone 3 DLC maps.
You can play any of the maps and modes until you reach the rank of Sergeant. If you want to keep playing, attain higher ranks, and earn any of Killzone 3 multiplayer's four exclusive new trophies, you have to unlock the full version for only $15 (UK/EU price TBA).
If you unlock the full version you get a 24-hour double XP bonus, three free unlock points, the ability to set up clans and custom games, and access to the Botzone mode.
Meanwhile, Guerrilla announced an "anniversary treat" for those who already own Killzone 3 or who buy the full version of the multiplayer.
Next weekend is a double XP weekend, starting Friday, 2nd March, at 5pm UK time. It ends on Monday, 5th March at 10am UK time. The trial version of Killzone 3 multiplayer is excluded from the double XP weekend.
Guerrilla put out a new Killzone 3 multiplayer trailer, below.
ORIGINAL STORY: Sony will release the Killzone 3 multiplayer as a free download.
Next week you'll be able to download the multiplayer portion of the PS3 exclusive FPS for free from the PlayStation Network, the latest episode of the PlayStation Blogcast has revealed.
It goes live on Tuesday, 28th February in the US. Presumably it launches in Europe a day later, on Wednesday, 29th February. We're checking with Sony now.
The standalone offering includes all the maps, but there's a catch - an unspecified level cap. There will be a limit on what rank players can achieve in the free experience, and a limit on the number of skills and unlockable weapons available.
To unlock the full Killzone 3 multiplayer, you have to pay $14.99.