I use the TurboScan application on my iphone to scan music. It's fast and accurate. It produces a 300 dpi black/white image as a PDF, which can be emailed easily. The trickiest part is getting the phone exactly parallel to the image to be scanned, but this could easily be solved with a home-made holder for the phone. The program uses the iphone's camera and flash to get a decent exposure. Here's the link.