An official Amazon shopping app for iPhone and iPod Touch is now on the App Store. You'll be able to do pretty much everything you can on desktop - use Amazon's 1-Click purchasing, track and modify order, get recommendations, view user and editorial reviews, and access your 'wish list'.
We like the sound of the 'Amazong Remembers' feature - take a photo with your iPhone and you'll get a product match with something on Amazon.co.uk and the thousands of Marketplace sellers. Then you can buy it, save it to your account, and make price comparisons.
Free, at the App Store.