Today's upgrade of Microsoft Virtual Earth brings with it a surprise. Hidden away in the Collections menu is an 'Add a 3D Model' item. Follow that and before long you'll have a "technology preview" version of Virtual Earth 3DVIA installed.
The software has a highly simplified tool set that is reminiscent of Sketchup's basic tools. Simple though they are, I am sure that plenty can be done with them. As yet I can see no way to import existing models to the software, which is something of a disappointment. However, it does at least allow you to save your work to the local machine, so models can be created at leisure before being published to Virtual Earth.
Clearly Microsoft are serious about competing with Google in the virtual world stakes. They have adopted a similar strategy of making a 3D modelling application freely available to the masses.
The ante has certainly just been raised.