Virtual Geomorphology - an odd, but useful site that endeavors to be an on-line textbook and encourages submissions to foster internet scholarship
Earth and Moon Viewer- impressive site providing live images of the Earth and Moon from satelites; images from many perspectives, any location with known coordinates; also has software
NASA's Earth Oberserving System: project monitoring long term global conditions on land surface, biosphere, atmosphere and oceans through a satellite network
RockWare- geology software for the petroleum, mining and environmental industries
