Small ideas:
Zebra (http://zebra.sourceforge.net/) is also great for decoding UPC/EAN - for linux it supports live-capture from a webcam, windows image files only. Works well even if the barcode is rotated some degrees.
German users may have a look at http://openean.kaufkauf.net/ - nearly the same concept but german.
I have a little setup to fetch metadata for my dvd/cds based on a Webcam, Zebra and Amazon/IMDB. Its mostly c&p from mythtv, http://www.linux-magazin.de/heft_abo/ausga...kettenschwindel (german) and http://amazon.com/soap