Little Boxes on the Noodle Incident offers CSS information on how to create various layouts. If you start from the main Noodle Incident page you will find all sorts of other fascinating info on this site as well.
Web Nouveau has a large collection of links to tableless web sites that can be inspiration to students trying to learn to work with CSS positioning and escape from layout tables.
css/edge is an effort at creativity and innovation with CSS. Demos, resources and explorations.
glish.com : CSS layout techniques offers up 2, 3, and 4 column layouts with the stylesheets ready to use immeditely. Wonderful resource.
TopStyle Cascading Style Sheet (CSS) Editor is an excellent CSS tool. It is Windows only, but offers a clear interface for creating style sheets, provides lots of tips about what may or may not work with various browsers, and is highly rated.