The Woopid Video site features free, screencast tutorials on various topics, including Office 2007. The 1-3 minute videos include Beginners Guides and Tips to Word, Powerpoint, and Excel. There are 137 Word videos, 120 Excel videos, and 75 PowerPoint videos.
From the Bundles page can scroll down to the Office section on the right, or use the Search field at the top to locate the tutorials you need.
Other topics include: iTunes, Vista, iPhone, Blackberry, Facebook, Firefox, etc.