Arcturus on 24 September 2008
I haven't heard anything about trophies being added to GTAIV. The following site does a good job of tracking games that have trophies, will have trophies, or are going to receive a trophy patch at some later point in time.
http://www.thesixthaxis.com/ps3-trophy-faq/
I doubt Rockstar will be releasing a trophy patch for GTAIV.
