Google has rolled out a shopping application for Android called - imaginatively - "Google Shopper". It lets Android phone owners search for products in several ways - by barcode, by taking a picture, with voice search, and using good old fashioned text.
When you've found products, you can view reviews, specs, pick favourites to save for later and - all importantly - view what prices it's available at. For the time being it only works in US dollars, though. It'll store your favourites offline - in case you need to look something up while out of mobile reception - and you can share items with friends.
It's a free download from the Android Market, and it's compatible with all versions of Android - we tested it on an HTC Hero without any problems - even features that weren't previously available on 1.5 (like voice search, and Google Goggles) work fine. If you're an Android owner then grab it and give it a try.