All PS3 games must support the Trophy system starting in January, 2009. That’s a mandate straight from Sony (“Yes from Jan 09 all games must have trophies”), so no publishers will be able to opt out.
Trophies, if you’re not familiar, are the PS3 equivalent of Achievements on the Xbox 360. You get a trophy every time you accomplish some amazing feat. Beat every level, collect every item, etc. It’s a lazy way to add replayability, to invent a word, to a game. Even World of Warcraft has them now.