In a nut shell, it is a turn based spaceship combat game set in the 40K universe. Like 40K, you set a points limit to your fleet build with each race choosing from their respective fleet list. The field of battle will have asteroid fields, dust/gas clouds, planet(s) and moons for terrain. There are rules for different scenarios so each game will have its own set of victory conditions.
I'm planning on being at BG this Wednesday (23JUL08) with an ETA of 5-5:30. If you are around and would like to play a demo or talk about it, let me know.
John