Check out the new book from Microsoft Press: Windows Embedded CE 6.0 Fundamentals by Stanislav Pavlov and Pavel Belevsky.
Here's the book description in the Authors on words...
This book is intended for everyone who develops or plans the development of embedded devices based on Windows Embedded CE. If you are just learning about the Windows Embedded CE operating system, this book can serve as a starting point for further learning. If you are already familiar with Windows Embedded CE, this book provides advice and recommendations for application development.
Here's the chapter listing for the book:
This is a good companion to the existing book by Doug Boling that focuses on application development - Programming Windows® Embedded CE 6.0 Developer Reference, Fourth Edition