Multiverse is "A center of multicultural science education to support diversity in earth & space science."
The American Geosciences Institute have an array of curriculum materials for all levels, from elementary to college.
The Earth Science World ImageBank has photographs of all aspects of Earth Science, climate data from weather stations around the world, and an interactive game to discover oil
Geology.com has some useful resources for teachers, with teaching ideas, articles, and maps linked to satellite images
Ocean Sciences Teacher Resource Center
NOAA Ocean Explorer has lesson plans available