The U.S. Department of Agriculture Natural Resources Conservation Service (formerly USDA Soil Conservation Service) site, which includes on extensive photo gallery, is located at
www.nrcs.usda.gov/

Their World Soil Resources Office site is
soils.usda.gov/use/worldsoils

and the National Soil Information System at
nasis.nrcs.usda.gov/

with a general "Soils" website at
soils.usda.gov/

A set of online posters illustrating and describing the twelve soil orders is found at
soils.usda.gov/technical/soil_orders

The National Park Service engages in soil inventory and mapping activities:
www2.nature.nps.gov/geology/soils

The Smithsonian Institution and Soil Science Society of America have an online soils exhibit:
www.soils.org/smithsonian/index.html

The National Wetlands Research Center is at
www.nwrc.gov/

The Canadian Soil Information System is at
sis.agr.gc.ca/cansis

The International Union of Soil Sciences Working Group on Land Degradation and Desertification's International Soil Reference and Information Center is
www.isric.nl/

and the International Erosion Control Association at
www.ieca.org

Soil-related information at WRI's EarthTrends site can be found by clicking on "Agriculture and Food" at
http://earthtrends.wri.org/

A feature on the use of soil-chemistry mapping to address the selenium contamination at Kesterson is at
minerals.cr.usgs.gov/gips/na/0elemap.htm#elemap