Integrating with map services like Microsoft Virtual Earth, Google Maps can bring your CRM or SharePoint application great increases in features at a relativly low cost. Microsoft uses Microsoft Virtual Earth internally and the Microsoft SharePoint Products and Technologies Team Blog has written an interesting posting about this which includes a reference to a codeplex project including all code for the internal project.
I havn't checked it out, and it is used for SharePoint in the example but I believe that a lot of the code probably can be used to develop a Virtual Earth driven map service in Microsoft CRM.
So, without further ado, please read the posting and check out the codeplex project if you are interested!
CRM and SharePoint Consultant