NASA Software, Innovative Satellite Viewing + Open Source
"World Wind lets you zoom from satellite altitude into any place on Earth. Leveraging Landsat satellite imagery and Shuttle Radar Topography Mission data, World Wind lets you experience Earth terrain in visually rich 3D, just as if you were really there."
Using the application provides a sense of context and scope to visualizing satellite imagery that I have not experienced previously. The application is extremely intuitive to use. Scrolling the mouse wheel up or down will zoom the view in or out. As you zoom closer to an area, the application will download more detailed imagery from Nasa on the fly. The application is in beta and surely will be more stable and fast as time goes on. Nasa should release the satellite imagery as an optional download for the user who does not care to wait for nasa servers to download additional data as they manipulate the application.
What makes Worlwind even more appealing is the fact that NASA has released the source code as well, as is rightly appropriate for this tax-payer funded organization.