Need A Css Guide!

Anyone knows a nice (beginner/advanced) guide of using CSS. I have nominal knowledge but want to expand it, Any suggestions?
Does anyone has a good one?

cascading style sheets? i think this should be in linen world! :)

http://www.w3schools.com

check sharereactor.com as well

http://www.davesite.com.

Thanks everyone. I wasn't checking this for a while.
Here are some more CSS links if someone is interested
http://www.meyerweb.com/eric/css/edge/
The Noodle Incident
WebMonkey CSS Guide

For me, w3schools was the best. Thanks once again everyone.

I.am