I was discussing about free source Geospatial tools the other day with my buddies…and world wind was one among them..Here's an excerpt taken from NASA'S website..please click on the link to get more information…There's wealth of infromation already avaialble on this..Ping me if you need more information.
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.
Virtually visit any place in the world. Look across the Andes, into the Grand Canyon, over the Alps, or along the African Sahara.