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.
calibre - Ebook manager, viewer & converter
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.
FBReader - FBReader is an e-book reader for various platforms. Features:
Ultimate eBook Creator - Ultimate eBook Creator is a dedicated eBook creator for creating the books for the Amazon Kindle.
Google Play Books - Google Play Books lets you search, preview, and buy millions of books using Google Book Search.