I use ZXing to scan a regular barcode (not QR code) and I get a scanresult string, or to be more precise a number.
When I scan QR codes, it's easy to use the result because it always contains a URL to the Android Market. But how to use the number from a regular barcode? Which "search engine" to use to get the right product?
PS. quering this result number via google.com or Google Shopping returned no product at all
If it's an ordinary 1D barcode, it might turn up in the UPC database. Other than that, there's not a strictly universal barcode database. Amazon's ecommerce API might help (it supports UPC lookup, but I don't know if it supports non-current products), and if you're in the UK then Tesco's has one as well that's worth a look.