As it's name suggests it's targetted at Classic content, digitized and made available by Project Gutenberg, after some clean-up and cover design by these guys.
"Classic", rightly or wrongly in this space is becoming a synonym for "Out of copyright, and free". The app costs $2.99 at the Apple App Store.
From the available screen shots at AppleInside and their own web (http://classicsapp.com/) they seem to have done a nice job on the aesthetics front, which was much needed for Gutenberg content in my mind.
I won't re-write the original AppleInside article to check it out, but just to show one more image of how they have taken a detailed and subtle approach to the content's appearance and page turning.
Whether those are the right design decisions to have taken from a readability and usability point of view, or not, I'll leave to experts to debate. But you have to admit they've done a "nice" job of what they set out to do. This attention to detail and presentation is also reflected in their web.
I'd welcome comments where from anyone who either reads regularly (or a lot) on the iPhone or who has tried this application.