From A List Apart this morning:

One of the nice things about old-school table layout methods is that they enable you to create liquid page designs very easily. If you want to center content vertically or stick a footer to the bottom of the browser window, all you have to do is include one main table with a height of 100% and position elements inside of it.

With web standards, you can't do this anymore. The table height property is deprecated in XHTML, and web standards recommend that you avoid using tables for page layout. [...] This article explores the ways you can position footers using web standards, although the same techniques may be used to vertically position other elements.

They go on to show you some wonderful standards-compliant CSS and javascript to help you recreate the footer hanging from the end of your table...