The LearnList

www.w3schools.com/css/
www.htmldog.com/guides/cssbeginner/
www.echoecho.com/css.htm
www.htmlgoodies.com/beyond/css/index.php
www.alistapart.com/topics/code/css/
http://video.google.co.uk/videosearch?q=css+tutorial#
www.richinstyle.com/guides/introduction1.html
www.westciv.com/style_master/academy/css_tutorial/
http://css-discuss.incutio.com/
www.456bereastreet.com/lab/
www.cssbasics.com/
www.blooberry.com/indexdot/css/propindex/all.htm
www.cssplay.co.uk/menu/
www.tizag.com/cssT/
http://alvit.de/handbook/
http://cssdocs.org/
www.stylegala.com/features/css-reference/

CSS: The Missing Manual (Paperback)
The CSS Anthology: 101 Essential Tips, Tricks and Hacks