They have them all but that one? There are tons of tactical RPGs on PC. It's just the tactical JRPGs that consoles have the market on. And that's not really what I feel like playing, though I do have a PS3 if I decide to get one later. --- "What's a strategy game? You mean like Mass Effect?"- A console gamer
here you go: http://store.steampowered.com/sub/33525/
some of the best SRPGs ever.
I recommend starting with Avernum: Escape from the Pit (which is a remake of Avernum 1)
If you want the original Avernum 1-3 (not on Steam) you can get them from gog.com --- "The easiest way to stop piracy is ... by giving those people a service that's better than what they're receiving from the pirates." ~ Gabe Newell.
Expeditions: Conquistador. It went under the radar for some reason, but is a fantastic game IMO. A bit rough around the edges in some ways, though. The biggest fault I can think of is that the AI is a bit dumb and easy top exploit.