Side color if 1024x768
I'm building a site that is built for 800x600 viewing. It has a yellow background.
Now if someone views from a larger screen, I want both sides, whatever isn't used by the main page to be red. and maybe eventualy have an image running down the sides.
I thought of doing it with a table, but then I realized that anyone viewing 800x600 would have to scroll to the side in order to view the page.
Put your layout in a container (or style the body element itself), make it 800px wide (should be less than that actually - about 760-780px) and give it margin: 0 auto.