Here are some websites I have found useful when learning css:
via Css Tricks:
Update ( 28 July 2011 ) :
Now for some excellent tools:
- Sass (http://sass-lang.com )
- Compass (http://compass-style.org ) Compass builds off of Sass to provide cross browser frameworks.
- Css3Pie Provides Css3 support (of a sort) for IE 6-8. Compass integration is available.