Users can view maps of locations around the world, find directions and overlay both. From the screenshots on AI it looks to be at a fairly advanced stage. Interestingly I noticed a check box in the preferences that allows Google Earth to render using OpenGL or DirectX. Considering DirectX is for Windows, would it be possible that this is actually built on an Intel Mac? If so, is it a universal binary that can run on Windows or Mac? Could it be that Google Earth for Mac OS X is built using Dharma, a “true” universal binary rumoured to be back in development at Apple?