Google SketchUp - Google Earth
    Google SketchUp is a free 3D modeling program provided to the public by Google.  This program allows anyone to create and post 3D models online through Google Earth.  Google earth allows for users to upload 3D versions of buildings and structures so other users can view them.  This process is like a wiki for 3D mapping.  Other users can comment on buildings that have been posted to show inaccuracies.
 
I worked with Google SketchUp and made a 3D version of my parents house, which I can upload onto Google Earth.  Here are a few images: