Some might think this is a long overdue piece of functionality, but at long last, I've got a working sample of integrating WorldMaps and Virtual Earth. I demonstrated how this works in a recent MSDN Roadshow Chad and I completed recently in Charlotte.
To check out how this works, you can see my modified stats page here:
If you're using WorldMaps, just point to worldmapv2.aspx instead of worldmap.aspx for the reporting page. Eventually I'll roll the functionality back into the original version.
Near the top of the page, there's a Virtual Earth link that will display this version of the map. Click this link, and when the Virtual Earth version loads, you can browse and zoom the map interactively.
Read the whole post for a description of some of the challenges involved in plotting tens of thousands of datapoints on a map, and how Brian has decided to solve them.