To celebrate the first anniversary of Killzone2, Killzone.com is hooking up 400 people with DLC codes today via twitter– one hundred for each Killzone 2 map pack, and another hundred for the full DLC bundle, including all map packs and multiplayer weapon!
To enter this promotion, use twitter and mention @killzonedotcom during the Promotional Period with the following message:
“@killzonedotcom Happy birthday Killzone 2! [your PSN Online ID], [your country]”
See complete promotion rules here