National Geographic Videos for kids: http://kids.nationalgeographic.com/Videos/
NASA Video Library: http://search.nasa.gov/search/search?q=video+list&output=xml_no_dtd&sort=dateADALAd1&site=nasa_collection&ie=UTF-8&client=nasa_production&oe=UTF-8&proxystylesheet=nasa_production
Get Energized - Video - Energy in Alaska: http://www.blm.gov/ak/getenergized/start.html
PBS Environment Cartoon Video: http://pbskids.org/eekoworld/index_flash.html
Food Chain, Lightning, Space Shuttle: http://www.kidsknowit.com/interactive-educational-movies/index.php
How Things Work List of Videos at bottom of page: http://videos.howstuffworks.com/Earthquake_101-video.htm
Virtual Field Trip of Volcanoes and Caves: http://volcano.und.edu/vwdocs/kids/fun/fun.html
Desert USA video page: http://desertusa.com/video_pages/food_movie.html
PBS - American Field Guide videos: http://www.pbs.org/americanfieldguide/topics/earth/index.html
Biome Videos - click on the biome - most have a video - The Wild Classroom: http://www.thewildclassroom.com/biomes/alpinetundra.html
Kratt's Creatures - Play a Game and see the video: http://pbskids.org/krattscreatures/flash.shtml