You can get the files in the download sections here:http://freespace.volitionwatch.com/
Be warned, lots of annoying pop-ups on this site.
Freespace was made by the same people as the original Descent games (Volition). It had nothing to do with Descent, but that was part of the original title to try to make it more appealing to an existing market. (The original Descent was the game you're thinking of - 3d shooter in a mine).