Currently, I am running X in 1024x728 resolution.  When I Ctrl Alt - to
change resolutions to 800x600, I get a 800 x 600 virtual window of my
1024x728 desktop.  When I move my mouse to the left edge of the screen, the
screen scrolls until it reaches the end of the 1024/728 desktop.  Is there
any way to actually change the desktop resolution to 800x600 (or 640x480)
and avoid this problem?

FYI, the reason I want to do this is so I can play Starcraft under winex.

Thanks,
Gene