This is one of the essential Android Applications. While apps like ShopSavvy do a whole lot more, they are actually BUILT using THIS Barcode Scanner as a starting point. I love the ability so just one-tap jump into the app and scan a barcode with the highest level of simplicity.
If you look on the AndroidApplications.com application pages you'll see codes like this:
These are called "QR" codes. If you open up barcode scanner and AIM it at the QR code it will take you directly to that application on Android Market. Depending on what QR code you scan it will bring you to a special webpage designed just for that QR code.
If you haven't used a barcode scanner or started using QR codes you NEED to. Once you start you'll never look back as its an amazingly quick, fun and convenient way to find the information you want and need!