Free CSS Tutorials
CSS Tutorials at W3Resources
These tutorials cover CSS 2.1 and include references and examples
CSS Beginner Tutorial
In addition to the beginner's tutorial there are links to intermediate and advanced tutes, the latter of which includes CSS3.
CSS Tutorial, PageResource.com
Tutorial, properties, including a section on CSS3.
CSS Tutorial at tutorialspoint.com
This tutorial covers both versions CSS1 and CSS2 and teaches you CSS starting from basic concepts to advanced concepts, includes a reference, quick guide and color charts.
CSS Tutorial at HTML.net
16 lessons including positioning and floating elements.
Comprehensive site from W3Schools.
This website includes an introduction to CSS, a tutorial and additional resources.
RichInStyle.com CSS2 tutorial
CSS Tutorials, House of Style
Tutorials and shortcuts.