Just before Christmas, the Rockstar Network discovered a listing on the ERSB for PlayStation 3 versions of Grand Theft Auto III and Vice City. No more information that that, just that in some form, those games have been rated for release on the PS3. Those listings have since disappeared, but the excitement about a potential HD collection has not died down.
Funnily enough, the bestselling game on the PS2 and a constant favourite amongst GTA fans, San Andreas, wasn't rated (or at least wasn't made public). Make of that what you will, although it does seem a very strange omission. The announcement of a Grand Theft Auto III HD collection would excite a lot of people and, let's be fair, is long overdue.
On the other hand, there's the chance that nobody wants to spend months giving the collection the HD treatment and that these will come out as a PS2 classic on the store instead. If that was the case it'd be presented exactly the same as it was when released, without updates or trophies. It seems unlikely, if SCEA really are acting as publisher on the re-release, a 360 version seems unlikely. In short, watch this space.