Barcode Scanner

I'm working on an Arduino project that entails using a barcode scanner with a USB interface. Could this work with a USB shield, what model/brand USB shield should I purchase, and how do I get the Arduino to read the barcodes and store them? Is there some sort of library for this?

If you had to develop this from scratch I would go for a RS232 bar-code scanner, but it looks like someone has already worked out how to do what you want.

Courtesy of the Google Machine, as my old boss would say.