The Imaging Radar's web site is based out of NASA's Jet Propulsion Laboratory. The Physical Oceanography Distributed Active Archive Center archives and distributes data relevant to the physical state of the oceans. The site includes Physical Oceanography from Space for kids. The View from Space - NASA Series of shuttle photographs depicting landforms of Kansas. This defunct archive was created to study the effects of the Kuwait oil fires on the environment.
Some screen grabs are still available and interesting to look at.
Landsat Thematic Mapper Data Sets Numerous 512 x 512 TM scenes that are excellent for classroom exercises and experimental research projects. The Langley Atmospheric Sciences DAAC is responsible for the processing, archival and distribution of NASA Earth science data in the areas of radiation budget, clouds, aerosols, and tropospheric chemistry. Data sets collected for both atmospheric monitoring and terrestrial mapping are available at this site. Observatorium - NASA NASA's Observatorium is a public access site for Earth and space data. It has pictures of the Earth, planets, stars, and other cool stuff, as well as the stories behind those images.