Below find a link to an Amazon Kindle user forum where users compare their experiences and happinesses reading Kindle books on iPhones using the Kindle iPhone app. Many people are very happy with this experience -- *personally* I can't imagine it [sort of like watching a movie thru a peep hole] -- but that doesn't mean there aren't other people who are happy with it! http://tinyurl.com/nqyspj But this is somewhat of a different issue than PDF + Kindle DX in that the Google Books approach of simply digitizing the page images of a book is a perhaps reasonable approach where the readership for that book is small compared to the effort required to take the Gutenberg approach of producing a clean digital text. If one is going to simply digitize the page images of a book then one needs a reader with a screen big enough to display that page image legibly -- unless one imagines a technology to slice and re-dice the page image in an intelligent manner so that snippets of the page image fits readably onto an iPhone.