Awesome, but for those of use without an iPad, there is still www.gutenberg.org. They don't have that many beautiful illustrations, but they have far, far more literature and they are all in text files.
http://www.gutenberg.org/ebooks/1342 Pride and Prejudiced
http://www.gutenberg.org/ebooks/28054 The Brothers Karamazov
http://www.gutenberg.org/ebooks/1524 Hamlet
http://www.gutenberg.org/ebooks/28233 Sir Isaac Newtons Principa mathematica
http://www.gutenberg.org/ebooks/14986 Experimental Research in electricity by Michael Faraday
http://www.gutenberg.org/ebooks/215 Jack Londons call of the wild
http://www.gutenberg.org/ebooks/103 Around the world in 80 days
http://www.gutenberg.org/ebooks/3748 A Journey to the center of the earth
It would be great if Gutenberg had a nice, polished app browser interface like this. I've loaded a bunch of stuff from Gutenberg on my iPad but the process is pretty clunky.
Isn't the Project Gutenberg catalog available on the iBooks store? (Here in Austria it's the only thing on there. Thank's very much publishing cartels...)
There is an app called something like Eucalytus which is designed to integrate with Gutenberg and which renders the books stunningly beautifully. It is designed by somebody with a streak of OCD so when you turn the page they snap in but they also react as actual paper would with regards to speed, number and points of curl, etc.
I don't know if there is an iPad edition, but it is really good for iPhone.
Also, I find it hard to find stuff that I want. You can browse the top hundred titles, or you can browse every damn title in the system, but the in-between ground is iffy.
The only sad things is that there are more books there than I will ever have time to read.