Best R* game ever, by a long shot; and well worth $7.50. Any gamer who hasn't played Bully is seriously missing out.
That said, I've also heard nothing but negative comments about the quality of the PC port, so CAG's might be better served by putting the $7.50 towards the 360 or Wii version. Even the PS2 version is fine, just keep in mind that the framerate is lower than most PS2 games, but it's definitely playable.