The app does not make a direct connection to the Kindle store. You'll have to use Safari on the iPhone, iPod touch, or computer to actually buy the content. If you own a Kindle already, you will be able to sync the books you have over to the iPhone.
Amazon says it has been working on the software for months, and sees it as a gateway to get people interested in buying a Kindle.
One of the advantages of the Kindle app is that you will be able to see color illustrations in books, something not possible on the Kindle hardware, which only shows images in shades of gray.
The iPhone version of the software does not have the controversial text to speech feature that has raised the eyebrows of companies selling audio books. Friday, Amazon said it would let publishers selectively turn off that feature on the Kindle.
Thanks to everyone who sent this in.