GCFLearnFree.org is a program offered by the Goodwill Community Foundation. The site offers free training and tutorials as part of their mission to "... create and provide education, employment, and life enrichment opportunities for people who desire to improve the quality of their lives."
The site features over a dozen self-paced free Excel 2007 tutorials, covering everything from setting up Excel 2007 to using conditional formatting and creating pivot tables. Before you get started or after you have completed one or more of these free tutorials, you can take a test to determine how much you know about Excel 2007. The tutorials do not require you to download any software or provide information. However, if you opt to take the knowledge test you will need to create a free user account.

click to enlarge