Matt Gemmell gives a high-level look at what you’re getting into if you decide to publish a work via the iBooks Author app.

I’ve spent a the majority of my afternoon working in iBooks Author, and it is very simple to use. If you are wanting to ship a book that does not require this deep functionality then it would not be too much more work to release your book as an eBook, a PDF, and an iBooks book (or whatever the proper term is for a work that’s been built within iBooks Author).

iBooks Author for Authors