Ah, the Instant Action. I should have looked more closely at that, but since it seemed the same as single player I didn't go all through the menus. I'll try that out in the morning. It's great it's such an extensive game with so much replay value. I was just checking out the Galactic Conquest option. Thanks Darth Andrew, and thanks for the welcome!
Awesome game. I just passed the Xbox singleplayer missions, ending with Endor. I thought maybe passing them would allow me to replay as the opposite faction on each of those levels, but doesn't seem to be the case. I remember trying the Xbox demo that came on the Trilogy DVDs, and there I was able to choose Rebel or Empire. Was this just for the sake of demo purposes?