The Panels module is an essential tool in the box of every site builder. Panels enables you to make custom layouts quickly and easily with a drag-and-drop interface. Panels is highly extensible and can leverage content, users and taxonomy.
Drupalize.Me offers a series of free videos that explain how Panels can rock your site.
Chapter 1.) Introduction to Panels
Chapter 2.) Creating Multicolumn Pages with Panels
Chapter 3.) Adjusting the Settings for Each Panel Pane
Chapter 4.) Creating Different Versions of the Same Page with Panels
Chapter 5.) Duplicating Variants by Cloning