Zoom Astronomy — Links about astronomy (stars and planets)
Kidsastronomy.com — This site includes information about planets, comets, constellations, galaxies, and more. It has a teacher's resource section, as well as games.
Astronomy: Our Place in Space — Use with caution. This site includes a lot of evolutionary references, such as "billions of years ago," and states that the Big Bang caused the universe. However, it does have some good factual information about the solar system presented in a kid-friendly manner.
Astronomy Charts — This interactive site shows current sky maps according to zip codes.