The Digitally Distributed Environments blog posted an interesting article about creating 3d Panoramas using Google Earth. I'm sure you have seen 3d panoramas before, either of the insides of buildings, or of open areas / views. This technique however produces the same effect using Google Earth's satellite imagery.(click the image below to see the 3d Panorama using QuickTime VR)
The panoramas are created by taking a series of screen shots from within Google Earth with the view rotated around a fixed point above the map and then adding a fake sky texture. This technique could easily be used to show 3d buildings in the view as well.Of course there is one major problem, using this technique commercially is almost certainly against Google Earth's terms of use (see this post in their faq section). How you would go about getting permission to use these, or the costs involved I have no idea. If anyone does (google?) please let us all know.