Usually a flatbed scanner that connects to your computer using a USB cable.
Whichever scanner you use, you will need to have the appropriate software to run it, but this is usually supplied with the hardware. Perhaps more annoying is finding the proper setup for it, to accommodate for Japanese printing methods.
Why this tutorial is needed ?
Scanning is usually pretty easy and straight forward: put the book on the scanner, click scan, presto!
But if you do that with a Japanese book, i.e. the Final Fantasy Ultimania, you will get a crummy picture, like the one below:
See the rest of the tutorial at my forum
Scanning Pictures from Japanese Books & Magazines - Final Fantasy Project