While Amazon has a pretty good mobile website, a dedicated application gives the developers much more access to a smartphone's hardware. In the case of Amazon Mobile, this includes the camera, allowing you to scan barcodes wherever you are and find them in one of the biggest online stores in the world.
We reviewed Amazon Mobile over the summer, and found a useful application for the focused shopper:
Amazon is a huge store, and while browsing aimlessly through the store with only a vague idea of what you want to buy is something that can be enjoyable on your deskbound computer, trying to find 'something new for a Nintendo DS' on the smaller screen of a mobile can be a frustrating scroll through some huge lists. But that's not where the application's strength is. It's here when you have a retail itch to scratch and you have to buy something at that very moment in time. You can zap with the barcode, you can punch in an ISBN number, you can search with laser-like accuracy, and then you press buy.
And a day or two later, what you wanted will be on your doorstep. It's the closest thing to magic you will ever put on your mobile phone...
You can download Amazon Mobile for free through the AAWP App Directory.