Hoping to gain traction on a device with a much larger installed base than that of its own eBook hardware, Amazon has offered up a free application for the iPhone bearing the Kindle name. The new program instantly becomes the iPhone book reader with the broadest title selection--the entire selection of books available for reading on Amazon Kindle can also be read on Kindle for iPhone.
Amazon, in a bid to keep its own hardware relevant, allows books purchased with the iPhone Kindle app to be transferred to the proprietary Kindle and Kindle 2 devices. Current owners of either Kindle can access their entire libraries through the iPhone app. Synchronization capabilities allow bookmarks and reading locations to be preserved during the sharing process.
Unfortunately, the Kindle application offers nothing new with regard to interface or usability. The ground it treads has been well worn by a variety of extant iPhone eBook readers, including Stanza and eReader. Those apps lack the title depth of Kindle, but offer similar if not superior book navigation and text display.
The Kindle for iPhone app also has some significant limitations relative to the Amazon hardware; periodicals such as newspapers, magazines, and blogs, and personal documents cannot be viewed on Kindle for iPhone. You also can't buy books directly from the Kindle for iPhone app. You'll need to go through a Web browser--Safari for iPhone should work--purchase a book, then designate an iPhone or iPod touch for delivery.