A ton of terrific type on Cascading Style Sheets at the Web Developer’s Virtual Library:
Style Sheets allow you to control the rendering, e.g. fonts, colors, leading, margins, typefaces, and other aspects of style, of a Web document without compromising its structure. CSS is a simple style sheet mechanism that allows authors and readers to attach style to HTML documents. It uses common desktop publishing terminology which should make it easy for professional as well as untrained designers to make use of its features. Visual design issues, such as page layout, can thus be addressed separately from the web page logical structure.