They've just released a demo of this game which is 380MB big. It's powered by the Freespace 2 engine but you don't need this game as this mod is entirely stand-alone. There's a version for Windows and Mac - a Linux build is coming soon.
Features:
Accurately detailed high-resolution ship models High quality, originally engineered audio Authentic, original in-game soundtrack, in addition to pieces by Bear McCreary and Richard Gibbs Original characters and voice acting A three mission single player campaign depicting never-before-seen events, interwoven with and true to the series’ storyline Head online and go head-to-head with your friends—and foes—in intense multiplayer missions including Deathmatch, Capture the Flag, and others Exciting Viper combat with authentic weaponry and flight controls
Here are some places where you can download this game:
Game Warden File Front The Cylon Base Internode Mod BB 4 Players Game Warden (the Mac version)
I also found a couple of trailers on YouTube:
The graphics aren't really top-notch but considering that this is a free open-source game it certainly looks very impressive.