Learning CSS » Whitespace
Some good links over on 9rules for those learning, or at least pretending to learn css.
If you are just beginning to get into design you really shouldn’t look at learning CSS as an option or something to do down the road. Start learning it immediately. It’s way beyond the fad stage and is a technology that allows you to reach the largest audience possible by being accessible (if done right) and customizable (different stylesheets for different formats).