Think Garden is a PBS sponsored video collection that helps teach elementary students about the art and science of growing food, with an emphasis on biological and environmental concepts. It also addresses topics related to nutrition and economics.
Lead your students in learning about natural resources used in common packaging materials. Challenge your students to conserve natural resources through their lunch choices.
Nature Explorers is a UK site with great resources for teachers and students to learn about our natural world. There are special tabs for each kind of exploration and each section has a teacher resource site.
Earth Matters 4 Kids is geared more toward upper elementary grades in environmental studies.
Eeko World from PBS is a wonderful site to use with students for Earth Day.