It's supposed to have trophies (even says so on the game's package) but there's apparently some issue with PSN. I'm assuming you have it for the PS3, since I know people who have it on the 360, and they've told me they still their trophies.
I was pretty ****ed off about that too, when I first realized it. I still kind of am, since it's the only game on the PS3 so far that I've put THAT much of my time and effort into. XD
Sadly, I doubt they'll fix the trophy problem; it's been five years, after all. If there was ever a time they were going to fix it, I imagine it would have been shortly after the game was released.