Pandamian is a super-simple — and free — tool to create an ebook. Sign-up takes a few seconds, and you’re given your own url address for all your future books. Click on “create a new book” and you’re off! You can easily copy and paste images, and readers can leave moderated comments. They can also subscribe to an RSS feed if they want to be updated on newer chapters. The only negative I see is that the books don’t appear to be embeddable, but perhaps I’m missing it (and I am — see a comment from the creator of Pandamian describing how to embed your creation).
I’m adding it to The Best Places Where Students Can Write Online.