Apple has rejected an app from Sony that would simulate Sony’s own e-book reader and allow customers to purchase books from Sony from inside the app. It’s part of a new Apple policy prohibiting any in-app purchases through channels other than Apple’s own iTunes system. This could lead to changes or eviction for Amazon’s Kindle app, which has had an app presence on the iPhone and iPad. That, in turn, could amplify the war of e-readers since part of the sales pitch for Kindle is that you can start reading your book on, say, your Kindle and then resume on your iPhone and then switch over to your computer.