The Starsiege development status page was updated with details regarding the soon to be released demo of this first person mech-er...HERC game:

The demo is finished and is almost ready for distribution. It should be released sometime this week. The Demo consists of the four training missions and the first two missions in the human campaign. It will be around 52 MB to download. There will be no multiplayer in this demo.

Thanks Datumplane. If you're like me and totally baffled as to what the heck a "Datumplane" is, by the way, they've been kind enough to set up a page for screwballs like us.