Google just added a Geo page to their Google Educators site. It gives helpful information on the applications as well as suggestions for classroom use.

http://www.google.com/educators/geo.html

Google Maps

http://maps.google.com

Google Maps is an excellent alternative to Mapquest, etc for driving directions. Besides driving directions, Google Maps offers many other useful features.

• Driving Directions: If you don’t like the route you’re given, simply drag and drop the route onto another road. Maps will automatically re-route you. In areas where Street View is available, get 360 degree turn-by turn-photos.
• Street View: In areas where available get a 360 degree street level view of a street, city or route.
• Traffic View and Predictions: See current traffic conditions or view traffic patterns.
• Email or Link to Map/Directions: Link, email or embed any map or set of directions.
• My Maps: Create your own personalized map with your favorite locations. Share with others so they can mark their favorite places.

Google Sky, Moon and Mars

http://www.google.com/sky/

To help you explore the far reaches of our universe, Google has teamed up with astronomers at some of the largest observatories in the world to bring you a new view of the sky. You can find the positions of the planets and constellations on the sky and even watching the birth of distant galaxies as seen by the Hubble Space Telescope.

http://www.google.com/moon/

To help you prepare, and to whet your appetite for exploration, Google teamed up with scientists at the NASA Ames Research Center to bring you this collection of lunar maps and charts. This tool is an exciting new way to explore the story of the Apollo missions, still the only time mankind has set foot on another world.

http://www.google.com/mars/

This map of Mars, published by Percival Lowell in 1895, was the result of many years spent carefully studying the Red Planet through his telescope. Now you can do the same through your web browser. In collaboration with NASA researchers at Arizona State University, Google created some of the most detailed scientific maps of Mars ever made.