I want to make a footer that stays at the bottom of the viewable window UNLESS it butts up against the content when you resize the window smaller.
I tried... bottom:0; p
I believe this will do what you want: CSS layout: 100% height with header and footer. I've used it on a site and it can be tricky to implement depending on the complexity of your existing layout.
I use the method as described by The Man In Blue called footerStickAlt - works a charm, CSS won't validate if you include the IE6 hack though.