The latest release of the Microsoft Dynamics CRM Software Development Kit (5.0.13) is now available for download here. It is also available in the MSDN library here. It applies to the upcoming CRM 2011 RU12 for On-Premise, as well as the CRM Online Microsoft Dynamics CRM December 2012 Service Update.
There is a lot included in this update and some reorganization of topics to make life easier. More details can be found on the CRM Team blog here.
Check it out!
Dynamics CRM Solution Architect and Trainer