PressBooks lets you and your team easily author and output books in multiple formats including: epub, Kindle, print-on-demand-ready PDF, HTML, and inDesign-ready XML.
PressBook seems a powerful platform for publishing, and I consider using it after I end the first writing phase of Zen of Teaching, which is being done with a WP plugin, Digress It, a wonderful solution that divides text into paragraphs and then allows comments to be attached to them. After the discussion around the text has finished, though, I’m thinking of PressBook to make the sort of final version before the virtual press.
I discovered PressBook through this interesting article in WPMU: An Introduction to PressBooks: A Digital Book Publishing Tool Built on WordPress, which also introduced me to Anthologize, a nice tool which allows to construct a book from a WP blog.
Here is a slideshow: