Google recently released Google Shopper, which is a free Android app for Android Market, that does voice and visual search. You scan scan barcodes and product pictures or perform a search by voice to get back detailed listings of prices, product reviews, and specs.
If all of this sounds familiar, it should. There is already another Google-made app for the Android Market by the name of Google Goggles, which will come preloaded in most, if not all, Andorid 2.1 handsets. Google Goggles, I believe, does not include the voice search feature, but performs the visual search promised by Shopper.
To download shopper, either scan the QR code at the bottom or do a search for “Shopper” in Android Market.