Google is set to announce a partially exclusive licensing agreement with Stanford that will provide automatically generated 3D models of buildings for Google Earth at Where 2.0. This is likely an attempt to catch up to Virtual Earth's comparable feature announced in November.
Read: http://blogs.zdnet.com/Google/?p=572
Similar to Virtual Earth 3D by msn/live (aka Microsoft)
Visit http://maps.live.com and click 3D and it will ask to install Virtual Earth 3D
(manual download) Download Virtual Earth 3D (for Firefox): http://go.microsoft.com/fwlink/?LinkId=83190
Note: Pay attention during the install as it will default two checkboses for msn/live search.
The msn 3D building look quite bad, (I know its a hugr job, but they still look badly rendered) hopefully Google do a better job...