Ripten reports:
"Steam has been picking up…city crims. The Grand Theft Auto 3 Trilogy might be making its way to Steam for download. The GTA1 & 2 have been up for download online for years, but it would be quite the gift from Rockstar to get these more recent titles. However, the release of the GTA trilogy isn't yet certain. The games have only had a phantom appearance on Steam, with only their title and a $0 price tag. When they are available for download we doubt they'll be free like their predecessors.
With GTA 3, Vice City and San Andreas on Steam, what could come after but the next generation sequel, Grand Theft Auto 4. If this is in the pipelines, expect to see it a year or so down the line after the initial console release."