Microsoft Press has released a new e-book for free (for a limited time only) titled First Look: Microsoft Office 2010. It contains 14 chapters which walk you through the newest features Office 2010 has to offer along with details of how they work. Interoperability with other applications has also been discussed as well as focus on how to work anywhere with Office 2010.
While Office 2010 is in public beta currently, this book can turn out to be really useful to spread awareness of the new features and provide training on them. The book is very well written with scenario based presentation, which makes it easy to understand.