Seems like a helpful website:

http://www.scantips.com/

Wayne Fulton's scantips is a goldmine of information, explanations and tips about scanning practice, and technology. I bought his book which has even more info, and illustrations. He's not a great writer and could have used the services of a good technical editor, but that is about my only criticism of the work.

Also worth mentioning (and linked from the scantips web site) is Hamrick Software's Vuescan software. An powerful, inexpensive improvement over the software that comes bundled most scanners.

http://www.hamrick.com/