Creating equal height columns with CSS is not as easy as it may first seem. This tutorial highlights the display problems that occur with multiple column layouts, and then shows a simple solution that works in all common web browsers. The method shown here is 100% CSS hack-free, image-free and JavaScript-free so it can even be used on the most strictly coded websites.

http://matthewjamestaylor.com/blog/equal-height-columns-cross-browser-css-no-hacks