Winners, drawn at random, get their names, gamertags or PSN IDs up on New York’s landscape in the game. You get eligible by tweeting “Hey @Crysis, I want you to put my name in the game! http://crys.is/contest #Crysis2contestNA” – if you’re in North America (except for Quebec. Fun is illegal there.)
The promo’s open to folks in the United Kingdom and Germany. They should send the same tweet but replace NA with UK or DE, respectively.
Full rules and mumbo-jumbo is here but remember “Approximate retail value of each prize is $US0.”
Crysis 2 [Official Site]