Desura for Linux launched a couple of days ago and Conquest is available there too.
If you don't know Desura, it's a digital distribution platform, much like Steam but more indie and mod focused, and without the imposed DRM. We like it. It's by the same folks who made ModDB and IndieDB.
If you purchase Conquest through Desura you can use the received keys for the versions downloaded from this site as well, even for Mac OS X. And if you purchased through another channel and would like to add the game to your Desura library, send me a PM or email us and I'll see it done.
I would also like to take this opportunity to encourage you to follow us on Facebook and Twitter. We do our best to keep you updated.