Worldwind is createdby NASA and is free to download. It is a model of earth with satellite photos overlay on the 3D terran, which you can fly over using different camera angle. The software also provide animation on different measurements on scientific data such as ocean current or cloud movement. The major drawback is that the ultra high resolution satellite photos only covers U.S. cities. There are major problems in overlaying city names of certain countries, hopeful this bug will be fixed on the next release. I had spent quite some time exploring and really fascinated by this virtual globe. It can be download at here