From their site: Welcome to the Internet UPC Database. This free service is run as a hobby of mine. This site isn't limited to UPCs any more. First of all, the term 'UPC' has been deprecated the new term is UCC-12. But the world has moved beyond that. As of January 2005, retailers in the U.S. are supposed to be able to support the EAN/UCC-13 code (the rest of the world has done this for years), which uses similar symbology, and one additional digit.
Barcodes, also known as UPC and EAN codes, let manufacturers and sellers identify and keep track of nearly every product sold or for sale. Developers can find the best APIs for creating applications with barcode functions on ProgrammableWeb. Here are ten of the most popular APIs highlighted.