Capcom's Christian Svensson has stated that PlayStatiopn 3 trophies are unlikely to be added to current games released due to the cost.
However, according to him Capcom is planning trophy support for future titles.
To quote Sven: There are a few titles released by our US group that we'd like to go back and have trophy support added to, but the bids to do so were cost prohibitive (they'd never make it through a green light process if those costs stand). We've not entirely given up yet though, so you may still see something further down the line.
Because there's some uncertainty, I don't want to say whether you will or won't on what's on that list.
I will say that future titles are planning trophy support across the board on our US developed side and I believe the majority of our Japanese titles are also (I'm just hesitant to commit because I don't have a complete list in front of me). More PlayStation 3 News...