Environmental Advocacy Sites

Discover Life in America (All Taxa Biodiversity Inventory)
Leave No Trace Outdoor Ethics
Wildlife Land Trust
Vital Ground
The Yellowstone Association
Pacific Whale Foundation
Foothills Land Conservancy
Glen Canyon Natural History Association
Friends of the Great Smoky Mountains National Park
National Parks Conservation Association 
Catalog Choice 
    (save trees and reduce emissions by eliminating unwanted paper catalogs you receive)
Sierra Club
Environmental Defense
Southern Appalachian Man and the Biosphere
Greenpeace
NRDC (Natural Resources Defense Council)
The Nature Conservancy
National Recycling Coalition, Inc.
Biogems
Earthwatch
Union of Concerned Scientists