Electricity and Magnetism - This website has many links to good Electricity and Magnetism sites. It covers electric circuits, power, batteries, conductors, insulators, resistors, electron flow, etc. It also covers magnets, magnetic field, electro-magnets, attraction, etc.
Ecosystems - This page has several ecosystem websites, including games, videos, and a tutorial. This includes the food web, producers, consumers and decomposers, etc..
Plant and Animal Adaptations - This page has several games and videos on plant and animal adaptations. Also includes endangered species.
Rocks and Minerals - This page has several tutorials and quizzes as well as videos on Rocks, Minerals, Earth's Structure, Plate Tectonics, Volcanoes and Earthquakes.
Intel - The Journey Inside. Give your students—and yourself—an opportunity to learn about technology, computers, and society with this collection of 35 visually inspiring interactive online lessons.
Energy - This page has energy sources, renewable energy and climate change