Hehe, I have two aliases setup just for that purpose. "full" puts it in full screen mode (1400x900) and "window" takes it out of full screen and pops the resolution down to 800x600.
There is a trick you have to do for this though (its quicker, at least). Before you put it in fullscreen mode, you have to set the resolution to your desktop's, then set the fullscreen variable. For window'd mode you have to do it the opposite way.