Google Shopper for iPhone: fast, accurate product search and price comparison on the go
The product cover art scanning seems to work a lot better for books than video game boxes, but the barcode scanning worked incredibly fast and accurately. The voice search is also up to Google's usual standards, but isn't activated by placing the phone to your face like the Google Mobile app for iOS.
It's strange that Google Shopper wasn't just built straight into the original Google Mobile app like Google Goggles was, but it's fast, free and handy, so there's no reason not to have this on your iPhone next time you go shopping.
Google Shopper for iPhone [iTunes] - Free