Hi! I'm happy you discovered my little app. It had its first binary release today, and it's looking quite a bit prettier than it was at those earlier screen shots.
The screen isn't quite that large--it's 160 dots per inch, which is quite a bit sharper than most computer screens. It's quite readable, however.
At the moment, installing Books.app (or any application, for that matter) onto the iPhone is a major pain in the neck. I'm working on a utility that will easily transfer the actual books to where you can find and read them.
Of course, the software is very much alpha--but I'm always open to suggestions and comments!