Pressbooks (now in public beta) is "a simple online book production tool, exporting books as: EPUB (for Kindle, iBooks, etc), typeset PDF (for print), and web (public or private). PressBooks is powerful enough for publishers, and simple enough for authors. It sits atop WordPress, but it’s a complete reworking, tailored for making and distributing a book."
Connected! Since the tool is built on WordPress MultiUser (each book is a “blog,” and each chapter is a “post”), this might be a great way to have students (or teams of teachers) collaborate on the creation of an eBook. There are plans in the works to also enable importing from an existing WordPress blog, as well as integrate social media and marketing tools.
Reported as the future focus of Pressbooks:
1. We want to help make it really easy and really cheap for all kinds of publishers (from single authors to huge companies) to make beautiful books in many formats
2. We want to really explore what it means to have “books” online as structured web objects…
Check out their demo slides, visit the PressBooks website and sign up to get started.