Today Microsoft Press released a free eBook for Office 365. Although I haven't read it personally, I've scanned through the table of contents...

If you're looking at Office 365, or already working with it, it may be worth reading. Especially since you can't beat the price on it.

Per the Microsoft Press info page:
This book shows you how you can use cloud computing—and ­specifically, ­Office 365—to get more done, collaborate more easily, and work more ­flexibly than you ever have before. From the necessary how-tos about ­creating and administering your Office 365 account and working with the various Office 365 programs to sharing files with your team, creating a team site, using Office Web Apps, and holding online meetings, you’ll discover how easy it is to work online and off, accessing and sharing your files whenever you need to. After you learn about each of the core programs, you can try strategies for building successful teams, and get some good ideas on practical ways you can put all this cloud power to work.
You can find more info about the eBook, and a download link here: