US Environmental Protection Agency
The federal organization which promotes the wellbeing of people and the environment.
http://www.epa.gov/

US Green Building Council
A non-profit which promotes green building through green building certification, green building education, etc. Learn more about LEED certification here.
http://www.usgbc.org/DisplayPage.aspx?CMSPageID=124

US PIRG
The US PIRG or Public Interest Research Group advocates for the health and well-being of the citizens of the United States. This site is a great resource with up-to-date information on current issues.
http://www.uspirg.org/

Utah Chapter of the Sierra Club
The Utah Chapter of the Sierra Club, a wonderful organization whose members work to save the earth and protect its wildlife. Their site has a wealth of information and helpful green resources.
http://utah.sierraclub.org/

Utah Department of Environmental Quality
Utah Department of Environmental Quality strives to protect the state's natural resources, regulating environmental laws and informing citizens of what they can do to help.
http://www.deq.utah.gov/