Amazon has released a free application that delivers Kindle book-reading to the iPhone, extending the company’s sales of e-books to devices beyond its Kindle e-book reader.

By using this app, you can read Kindle books using a simple interface. You can shop for hundreds of thousands of books, and wirelessly transfer them to your iPhone and iPod Touch.

Features include:

• Buy a Kindle book from your Mac, PC, or iPhone using a Web browser
• Read first chapters of any book for free before you buy
• Download the Kindle books you already own for free — they are automatically backed up on Amazon.com
• Adjust the text size, add bookmarks, and view the annotations you created on your Kindle device.

Amazon is no stranger to the iPhone. Amazon earlier released a shopping application that allows customers to find new items by letting them snap and submit photos of stuff they already own.

You can download the free Kindle app here. For now, the iPhone application is available for the U.S. market only.

[via TechFlash]