Really, your best bet is to use freely available CSS tutorials to learn. You can give Mulder's Stylesheets Tutorial a try (an oldie but goodie), and the W3C CSS Reference is an invaluable tool for both beginners and experienced designers. Good luck .
Here: _http://vandelaydesign.com/blog/design/web-20-design - very interesting tools for web design, "99 Resources for Web 2.0 Design", I often take many of them.