Sort of old, but still useful!
Div Positioning Review:
http://www.brainjar.com/css/positioning/
12 Lessons for Those Afraid of CSS Standards:
http://www.alistapart.com/articles/12lessonsCSSandstandards
Print Style Sheets (too cool, for printer-friendly versions)
http://meiert.com/en/blog/20070221/print-style-sheets-the-basics-for-no-excuses/
Floats, Lists, Selectors Tutorials
http://css.maxdesign.com.au/index.htm
Liquid Layouts:
http://www.alistapart.com/articles/multicolumnlayouts
