DIY Book Scanner
There are a number of reasons why you might wish to build a book scanner. This book attempts to document the process.
There is a forum at www.diybookscanner.org which has a lot of experienced users who can answer questions.
The basic book scanning process is scan, process the images, then possibly OCR. The alternatives to OCR are just viewing the pages as .jpgs, PDF format or DJVU. The traditional problem with OCR is accuracy.