This was to be expected.
Steve Jobs via GDGT:
The same controls, the same highlighting, the same bookmarking, the same PDF reading. If you get a PDF in Mail, tap on that and you’ll go right to iBooks. And, of course, the iBook Store right on your iPhone. We’ll have it on the iPad, iPhone, and iPod touch.
What can we do with all these products together? Well, the first is you can download and purchase a book to any of these products, and it’ll be wirelessly downloaded right to the device. Now, you can download the same book to all your devices at no extra charge.
With place syncing just like Kindle – Amazon should be scared. There are now 100 million devices that can buy books from Apple, how many Kindles has Amazon sold?