W3 Schools
In our CSS tutorial you will learn how to use CSS to control the style and layout of multiple Web pages all at once.
http://www.w3schools.com/css/default.asp

Noupe
The main idea behind CSS-based layouts is offering more flexibility and enhancing the visual experience of visitors. Some important tips and related key-factors can help to learn basics and keep essential techniques in mind. And this is what this article is all about. Finding the perfect Layout that have Total Flexibility, Equal Height Columns and just works fine.
http://www.noupe.com/css/css-layouts-40-tutorials-tips-demos-and-best-practices.html

CSS Max Design
Floatutorial takes you through the basics of floating elements such as images, drop caps, next and back buttons, image galleries, inline lists and multi-column layouts.
http://css.maxdesign.com.au/floatutorial/

Site Point
SitePoint is a fast growing online media company and information provider targeting the Web professional market, specifically Web Developers and Designers. The company has five major revenue streams: advertising and sponsorship, content-based products both online and in retail, software, and more recently streaming video subscriptions and classified listings.
http://www.sitepoint.com/subcat/css

Tizag
Learn how to seperate style and content on your web pages with CSS. Style your web pages with ease!
http://www.tizag.com/cssT/

html Dog
Like the HTML Beginner Tutorial, the CSS Beginner Tutorial assumes that you know as much about CSS as you do about the cumulative effects of sea squirt discharge on the brain chemistry of Germanic ammonites. The purpose of this guide is to teach the bare essentials - just enough to get started. The CSS Intermediate Tutorial and CSS Advanced Tutorial go into more depth about CSS.
http://htmldog.com/guides/cssbeginner/