I'm not sure if iPhone/iTouch will ever become a true e-book reader platform however Amazon have taken a few more steps towards it:
Amazon Launches Optimized Kindle Store Seamlessly Integrated with "Kindle for iPhone" App -- The Most Popular Books App for iPhone and iPod Touch
It seems like the site is "optimized"
for iPhone browsing and the iPhone app launches Safari when the user wants to "get books"
"Now when users of the a Kindle for iPhone app click on "Get Books", the new Kindle Store tailored for the size and shape of the iPhone and iPod touch screens automatically opens in Safari."
Well, I wouldn't call this seamless
but it's pretty cool even if it's just a skinjob.