If you have an iPhone and an Amazon Kindle, this will be a good news to you. Now, there is an application on the iTunes App Store that can read Kindle book on your iPhone. Not surprisingly, the app is called Kindle for iPhone.
The program is free to download from iTunes App Store. If you own a Kindle and iPhone, the application can synchronise with the Kindle so that the ebook can be at both devices (via Whispersync). However, text-to-speech function (a new function on Kindle 2) will not be available on the iPhone Kindle application.
Kindle on iPhone cannot access directly to Amazon’s Kindle store as what Kindle can do. So, instead, it uses its web browser to access the store to buy the ebook.
The biggest difference, I believe, is that iPhone can read the book in full colour while Kindle can only be in grayscales.