So far, PS2 re-releases via the PlayStation Network have consisted of forgotten classics. However, that's about to change with the re-release of the biggest blockbuster of the last generation. The ESRB has rated both Grand Theft Auto 3 and Vice City for PS3.
Given the listing (via Joystiq) claims Sony Computer Entertainment is the publisher, it's likely this re-release is a no-frills PS2 download and not an HD remaster, a la Ico and God of War. That's too bad, considering Rockstar Games did spruce up the visuals a bit when porting the game to iOS and Android for the game's 10th anniversary.
The final GTA game of the PS2 generation, Grand Theft Auto: San Andreas, has yet to be re-rated by the bureau. We've contacted Rockstar Games about what their plans for these PS2 games are, and will update when we hear back.