There are many websites that aggregate information or links to web-based resources. Only a few of the more general ones are listed here. There are several pages of the The WWW Virtual Library that cover different aspects of this broad subject, including Global Environment and Sustainable Development.
Because environmental studies is a problem-based area, almost every organization with a website of aggregated links represents a particular position. Caveat lector:
National Council for Science and the Environment's National Library for the Environment
EcoGateway
More specialized sites can provide focused searching. Government agencies such as the U.S. Environmental Protection Agency (a guide to this information-rich web site is available), the Vermont Environmental Board, and the United Nations Environment Programme generate and disseminate valuable information. Two websites that give you access to agencies are Government Information and Congressional Research Service. Other sites of more limited interest include:
Environmental History of Latin America
League of Conservation Voters' National Environmental Scorecards
U.S. Geological Survey's Fact Sheets
eldis, which features development and environmental information and full-text documents.