This is a must-read for any web developer interested in using CSS for layout for some simple explanations (with pictures!) and a pretty decent and quick overview of a lot of advanced CSS-layout topics.
Specifically pay attention to the Absolute/relative Positioning, Double-Rollovers, Faux-columns and, Sliding Doors methods. It starts a little slow, but go with it (and play with the examples).
On a side-note: at first I didn't pay much attention to the CSS-slide-shows-instead-of-PowerPoint, but it's really starting to grow on me. This presentation doesn't use it, but Erik Meyer has an excellent packaged solution to putting together your own CSS-Presentations. Go through the first few slides at least to get a feel for the functionality, then Print-Preview the presentation. Gorgeous.
URL: Pushing your limits