American Geophysical Union http://www.agu.org/
AGU is an international scientific society of 35,000+ members. AGU homepage has many hyperlinks to earth, oceans, atmosphere, space, and planets. AGU homepage welcomes members of the public, including students and teachers.
GeoForum http://www.geoforum.com/
Internet-based, technical information system. All Internet-based information contained in Geoforum.com is free of charge
Geologyone.com http://geologynet.com/indexa.htm
Geoscience news; earth science internet links; directories of earth science software and clipart resources; listings for scientific instruments; dealers of minerals and gemstones.