Other great tutorial sites:
Position is Everything!
-My favorite site for learning (by example) to replace table layouts with CSS.
CSS Layout Techniques
-Another great site with examples on multiple column layouts.
A List Apart
-Site full of great articles about the design process for CSS, as well as articles on different mini-tasks (i.e. pretty forms, multi-column lists, etc.)
Holy CSS Zeldman!
-A site with a bunch of links to tutorials to CSS concepts and applications.
Max Design
-Site with a bunch of tutorials on formating CSS lists, floats, and form selects.