A guy made a clone of this game for the PC and released it freely. It's called Grid Wars 2. It plays different from the XBox version, quite a bit slower and a little more emphasis on black holes. Works great if you have an xbox360 controller or any other dual analog controller hooked up to your PC.
Review:
http://worldofstuart.excellentcontent.com/grid/wars.htm
Download:
http://worldofstuart.excellentconten...GridWars54.zip