These are some great sites that I recommend. Sites that I have used information from are also included here.
http://www.wwf.org - World Wildlife Fund
http://www.wildaid.org - Wild Aid
http://www.redlist.org - IUCN Red List
http://www.nationalgeographic.com - National Geographic publication
http://www.snowleopard.org - International Snow Leopard Trust
http://www.saveindiastigers.co.uk - Save India's Tigers
http://www.davidshepherd.org - David Shepherd Wildlife Foundation
http://www.endangeredspecie.org - Endangered Species Lists and Information
http://www.bluegreenplanet.org - Fun and artsy e-cards -- "The earth says hello."
http://www.nhpa.co.uk - Natural History Photography Agency
http://www.endangered.fws.gov - US Fish & Wildlife Endangered Species Program