On my last job, we used hacked 770's with a battery-powered usb hub to drive a ccd barcode scanner. We wrote a web-based order picking application to pick orders in the warehouse.

We placed a wireless router high up on the warehouse racking to get broad coverage. We then had the ability to wirelessly check inventory status from anywhere in the warehouse. It was a cool system, and we put it together for around $250 per unit (770, hub, scanner, cables) which was way cheaper than most dedicated barcode readers.

This does not really answer the question of if you can read barcodes with the built-in camera, but you certainly can build a nice warehouse tool cheaply, using a hand-held scanner.