I learned the technique through “Google University” [read: I Googled it until I found an answer]. I wish I could give credit, but I’ve since misplaced the link I used. Thanks to whomever.
The technique involves creating an “everything but the footer” div, and setting it’s min-height to 100%. (For IE 6, set height to 100% – compensate for IE 6’s lack of support for min-height, and the fact that it auto-expands divs to fit content). Then you create a “footer” div as a sibling, and set margin-top to the height of the footer. Add a margin-bottom to the “everything else” div that matches, and you’ve got yourself a footer that stays at the bottom of the page.
Download the sample, and give it a spin.