MICROSOFT DYNAMICS CRM 2011 ONLINE
Empowering customers to create dynamic CRM systems for the Cloud.
F1 - CRM Protagonists, Users and Developers

Microsoft xRM Book and eBook

CRM as a Rapid Development Platform

The book below, while currently only being available for CRM 4.0, it is an excellent introduction to xRM and is available as both printed book from Amazon and as an eBook from the author himself.

Amazon UK - book link

eBook link