National Biological Information Infrastructure (US)
The National Biological Information Infrastructure (NBII) is a broad, collaborative program that provides increased access to data and information on the nation's biological resources. http://www.nbii.gov/education/

U.S Fish and Wildlife Services
Learn how the loss of habitat and ecosystems can lead to a decline in biodiversity, and how the Endangered Species Act helps conserve endangered and threatened species. This is a kid’s corner for educators and students. http://www.fws.gov/endangered/kids/#educators  

World Wildlife Fund (WWF)
A website that aims at preserving the delicate diversity of nature by raising awareness over endangered species, encouraging wildlife conservation, and helping protect animals habitats. http://www.worldwildlife.org/windows/