Tony Hawk's Pro Skater HD is on Steam for PC right now. Tony Hawk's Pro Skater HD is normally $10, but now through the end of the month it's down 10 percent to $9.
The PC version doesn't include the multiplayer modes – local or online – featured in the XBLA and PSN versions that launched earlier this year. Tony Hawk's Steam release includes four single-player modes and new objectives.
The Tony Hawk's Pro Skater 3 HD Revert Pack will hit as DLC for $5 soon after release, and includes three levels from that original game.