The recent announcement that
"Microsoft rejoins the Open Geospatial Consortium (OGC). The OGC is now responsible for making KML an open standard, so it is fitting that Microsoft should join a few days after adding support for KML in Virtual Earth."
is starting to make KML an interesting possibility as a standard for visualizing astronomical data. I am curious to see how this will evolve in the VO, but I believe MS's interest in a good thing.