Consortium for International Earth Science Information Network -- CIESIN
CIESIN, http://www.ciesin.org, is not an imagery index.  It provides worldwide information on human interactions with the environment. This CIESIN site is an entry point to a large number of earth science databases, and it allows users to simultaneously search different databases and rapidly identify and obtain data from various sources.   For details, see:  CIESIN Thematic Guide  useful for studies of human impacts on environmental change.   http://www.ciesin.org/TG/RS/RS-home.html;  CIESIN Social and Economic Data -- SEDAC a gateway to socio-economic data http://sedac.ciesin.org; and CIESIN Mapping and Data Fusion Tool an interactive mapping tool, http://sedac.ciesin.org/plue/DD viewer.
 

Environmental Information Systems in Sub-Saharan Africa
This ambitios effort seeks to compile environemtnal, socieoeconomic and remote sensing data for 44 African nations.  The project was too new as of Novemenbr 1998 to evaluate.
 

EU/ESA/G-7 Earthnews Page

Global Change Research Information Office Home Page -- GCRIO
The GCRIO provides users with access to global change and environmental data and information from around the world. GCRIO offers data directories, image inventories, data libraries, data browsers, bulletin boards, CD-ROM, and documents.

International GPS Service for Geodynamics
This site is useful for researchers who use the global positioning system (GPS) for studies in geodynamics. IGS archives and distributes GPS observation data and GPS satellite tracking station clock information. The project maintains a network of about 50 globally distributed permanent tracking stations. It also has Data Centers, Analysis Centers and a Central Bureau for information distribution. The bureau maintains Hot Links with allied organizations in Europe, Canada and the US.

United Nations Page - Earthnews