The videos on this site are pretty good too: http://howacarworks.com/. I think I payed $25 for access and it was worth it.

Thank you!

not online, but check out what is usually just called the idiots guide. Specifically "How to Keep Your Volkswagen Alive: A Manual of Step by Step Procedures for the Compleat Idiot". Everything I know about auto mechanics I learned from that book. Like this site, it is sprinkled with personality and anecdotes (of a Santa Fe hippie in this case), but as a learning resources it is excellent.