GamersDigest have received word from Seb Downie (Producer over at Guerilla Games) that the Killzone 2 servers are currently being updated.
"We are performing a server update and will also be deploying the game update straight after that to fix a number of issues.
The patch will be going live in Europe first and the US later on today."
The maintenance is expected to last no longer than one hour.
Update
UPDATE; The patch (1.20) has been released, it is 16MB.
UPDATE 2; List of fixes has been added.