Amazon’s Kindle, a software application for the iPhone, is available from the iTunes store here, for free. It works independently from the Kindle itself but if you had one and wanted to switch between the Kindle and the iPhone to read the same book, the system will sync up your bookmarks so you can seamlessly switch between the devices. Books you’ve bought for the Kindle will download to the iPhone and vice versa.
Browse for books in your browser, not the Kindle application, and send sample first chapters to your iPhone for free. After reading the sample chapter on your iPhone you’ll be offerd a “Buy now” link — which essentially is a 1 click immediate purchase of the book from the Kindle application, no confirmation offered nor required.