At first I thought this was a competitive move, but after reading it it's pretty obvious this is all about Apple not getting their 30% cut of the app sale - and perhaps competitive at the same time.
Last I checked, more people who own iPhone's/iPads still buy their books through Kindle than Apple's iBooks. By forcing other apps to use their payment methods Apple will either get a cut of their sales (that really high 30%) OR the other app developers will raise their prices to compensate, which I imagine will upset users and guess who's prices remain unchanged: Apple's iBooks.
I don't like the move, as it's ultimately bad for the consumer because that's who loses. You're either going to have to use Apple's inferior iBooks (and who knows what apps are next) or deal with slightly more expensive books in other apps because I doubt many of those other companies will be willing to lose 30% just because Apple says so.
It's moves like this that make it hard to support Apple. There's no denying they make great products, but at the same time, you hate giving your money to a company that you feel sort of strongarms you. Not to mention the stigma that comes with Apple products that you're a deuche, fanboy and/or idiot.
