Cascading Style Sheets

Glish says howto: http://www.glish.com/css/

W3C's official CSS page: http://www.w3.org/Style/CSS/

Two quick-starts they pointed to that got me going:

Actually, what triggered me to start messing with it was a page at scrounge.org:

http://www.scrounge.org/tips/fonts.html (scroll to the bottom)
http://www.scrounge.org/scrounge.css

Three columns, annotated: http://www.saila.com/usage/layouts/saila_layout.html

Show divs and spans: http://www.web-graphics.com/mtarchive/000300.php#000300