This just in from the SDK Team.

The downloadable Microsoft CRM SDK has now been updated: version 3.0.3. The MSDN online SDK has been published and will be live soon. The updated download can be found here: http://www.microsoft.com/downloads/details.aspx?familyid=9c178b68-3a06-4898-bc83-bd14b74308c5&displaylang=en

You can see more of the changes at Joris's Blog.

http://blogs.msdn.com/joris_kalz/archive/2006/02/01/SDK_for_Microsoft_Dynamics_CRM.aspx

Or if you like the british.. Simon also has some information on his blog...

http://blogs.msdn.com/ukcrm/archive/2006/02/01/522607.aspx