InfoStrat has published our WPF Virtual Earth 3D control on CodePlex. It is open source under the LGPL, and it is now live!
http://virtualearthwpf.codeplex.com/
This control comes in two versions: one for regular WPF applications and one with Microsoft Surface enhancements (multitouch pan and zoom gestures).
Previous implementation of Virtual Earth on Surface were done using transparent windows and the map itself had limitations (no rotation or transforms, etc.) due to Win32 interop.
InfoStrat.VE uses some magic to eliminate these restrictions. It also takes advantage of WPF data binding for controlling various properties such as the camera location. You can add pushpins by simply adding a WPF-based VEPushPin as a child element. VEPushPins can also be provided by a data-bound collection.
For examples of Microsoft Surface solutions we've built with this control go to our Single View Platform gallery
Founded in 1987, InfoStrat is one of the nation's foremost leaders in IT Services focused on Microsoft technologies. InfoStrat has provided IT Consulting Services on over 1000 customer projects. InfoStrat consultants hold over 150 Microsoft technical certifications and are experts in .NET application development focused primarily on Microsoft SharePoint, Microsoft Dynamics, and Microsoft Surface.