Awhile back I got
Bicycle Maintenance and Repair for Road and Mountain Bikes by Todd Downs.
http://www.amazon.com/Bicycling-Comp...8409361&sr=8-1
I like it a lot. I have prior experience with bike mechanics, but needed updating on the newer hardware. I got a used 2005 hardcover edition on Amazon for $5 shipped.
As others have mentioned, there is lot of info on the web. Park's website is really great.