More recently Programming Windows 8 Apps with HTML, CSS, and JavaScript by Kraig Brockschmidt:

http://blogs.msdn.com/b/jgalasyn/archive/2012/10/31/free-ebo...

This might be useful: Introducing Windows 8: An Overview for IT Professionals (Preview Edition) - http://blogs.msdn.com/b/microsoft_press/archive/2012/10/23/f...

Also, Windows 8 for Dummies: http://media.wiley.com/assets/7077/60/9781118554951_custom.p...