Digital Library for Earth Science Education (DLESE)
Great resource for finding online information and lessons about earth science. You can refine results to meet your needs for all different grade levels.
Provides over 150 links to teacher resources and student projects marked with appropriate grade levels for various topics including space, the atmosphere, soil composition, and much more.
Earth Trends: The Environmental Information Portal
Timely and accurate global environmental information through a searchable database with maps, country profiles, and much more is available on this site.