This is my space-combat rule set. It's moderately complex, with a frictionless movement system but without the reams of equations that usually accompany extremely realistic space games. It's a bit like the Pirate Game, you can play single battles but the full version plays more like a roleplaying game. If you just want the basic game, you only need to read parts one through five (movement, combat, ship types, weapons and equipment, and minifig combat). In a monumental lapse of judgment I have put the rule modifications for the microscale version of the game at the very end of the document, but they're fairly short.
http://www.brickshelf.com/gallery/thebl ... er/scr.doc