Earth

Google Earth can be a fun way to learn about a wide range of subjects.
 A. I learned that in the Google Earth 5, that you can navigate under the ocean and even explore the sea terrain. You can use a hide or display button to view the ocean's surface, and look just above it or just below it. I also did not know that Google Earth will allow you to see Mars and actually let you take a tour and record and video it. You can follow the path of the Rovers and see where they have been. This was very interesting and could be incorporated in an excellent science lesson for the students.
B. I looked at Elementary section and thought this was interesting as well. This site gave some wonderful ideas for lessons. The students could use Earth to recognize states, countries, oceans, etc. and even track rainfall. However, Earth could also allow more sophisticated assignments such as learning the US Presidents and finding the state where each was born. This site also gave an idea of learning about different monitory systems, and finding the country where the money was used.
C. The last thing I looked at was The Google Educators. This site was full of information. It tells how to get started using geo, and how to get classroom ideas and activities.  It suggested lessons using geo for subjects such as Biology/Ecology. History, Math and Physics etc.
Earth is a fun tool to work with and could add some fun interaction to the students.