iBooks Author - iBooks Author, free from the Mac App store, allows you to create beautiful Multi-Touch textbooks — and just about any other kind of book.
FlippingBook - FlippingBook changes the way you present your documents
Atavist - Atavist provides a suite of publishing tools to tell stories and build websites.
Scribd - Unlimited books, audiobooks & comics. Unparalleled discovery. Any device. $8.99/month
Mobipocket eBook Creator - Mobipocket eBook Creator is one of the easiest way to create a professional level of eBooks by simply providing some HTML and image files to your publication.
Flipsnack - Flipsnack | PDF to HTML5 flipbooks