Google has hooked up with Scholastic to distribute lesson plans (and a contest) to middle school students. There's a website for teachers and a special Google Earth page too.
Using Google Earth, teachers can fly their students around the world to talk to them about issues like climate change and how it has affected places like Glacier National Park, the Chesapeake Bay and Los Angeles. And they can introduce students to community initiatives across the country where volunteers are cleaning up their cities, planting trees and beautifying. Using Google Earth, teachers can show their students placemarks of the towns where outreach projects are taking place and students can get involved in cleaning up their own environment.