Alex Ramon, an experienced bike mechanic, setup a really great website totally dedicated to bike repair and maintenance in order to help people learn how to fix and maintain their own bikes.
He’s got over 40 videos posted, and the ones I’ve viewed are very well done. Each video covers a specific job, like adjusting the rear derailleur, reviewing each step clearly and concisely. Each video posting is also accompanied by a detailed write-up and still photos showing even greater detail where necessary. You can also download the videos or purchase higher quality versions on DVD.
Beyond the great video tutorials, there are also active forums on the site and links to tons of other great resources on the internet. Well done, Alex! Awesome site!