Message board, including sections for ask an astronomer, SETI, and space business.
http://uplink.space.com/ubbthreads.php
Discusses facts, mysteries, theories, and activities, about the solar system.
http://library.thinkquest.org/C0110484
Features a guide to the solar system for visitors of all ages with a scale model, interactive quiz, text, and images.
http://www.solarsystem.org.uk/
A collection of educational activities and resources based on Solar Oscillations Investigation (SOI) and Solar and Heliospheric Observatory (SOHO) data.
http://solar-center.stanford.edu/
An evolving list of those projects and programs in astronomy education to which anyone from around the U.S. can apply or from which anyone can receive materials.
http://www.astrosociety.org/education/resources/naep.html
College-standard introductory course to astronomy from University of Santa Barbara, California.
http://www.physics.ucsb.edu/~blaes/astro1/
Comprehensive, annotated hub site of resources relating to navigating by the stars, including theory, practice, history, instruments, and classroom links.
http://www.celestialnavigation.net/
Offers free lessons in astronomy. The course runs from Covers identification of stars, constellations and planets, and physics.
http://www.synapses.co.uk/astro/index.html