IDV Solutions has been building solutions on top of Virtual Earth and SharePoint for a few years now. IDV Solutions’s SpatialWiki product, from last year, was one of the first mapping solutions to be available in Silverlight, and was also one that could use a SharePoint list as the data source for an ad hoc collection of mapped items – allowing for disparate teams to construct, review, and edit a list of mapped datapoints, while also allowing for SharePoint management and business process capabilities on the data.
Today, IDV Solutions is launching version 4.0 of VisualFusion. Not only is this a very capable mapping solution using a Silverlight interface, but it also can be deployed (among other options) as a SharePoint web part, can utilize SharePoint list data, and can leverage the SharePoint Business Data Catalog.
You can play with a demo of VisualFusion 4.0 here.
VisualFusion is available in a number of different scenarios. Check out the version and package that is right for your company using the VisualFusion Comparison Matrix.