Conservation International Foundation- The goal of this organization is protecting endangered ecosystems. Take a look at the map of the 25 "hotspots"– areas that are most imperiled.
Endangered Species, U.S. Fish and Wildlife Service- Includes a complete state-by-state list of endangered and threatened species (both plants and animals). Hawaii has 297 species. 255 species in California. Delaware, 9 species, Nebraska, 13 species.
Home Page of the Nature Conservancy- Help Protect Endangered Species- The Nature Conservancy is a large, international organization that protects endangered species and endangered habitats by purchasing parcels of land and acting as a steward of those preserves. Go to the site index to find all of the topics covered.