Cool links with tons of information. Check them out:
Alternative Engery
Campus Center for Appropriate Technology, Humboldt State University, Arcata, CA
http://www.humboldt.edu/~ccat/
DOE Energy Efficiency and Renewable Energy
http://www.eere.energy.gov/
Solar Living Institute, Hopland, CA
http://www.solarliving.org/
Stewardship/Conservation
A Rocha, international
http://en.arocha.org/
Ecological Footprint Quiz
http://www.myfootprint.org/
Land Stewardship Project, MN
http://www.landstewardshipproject.org/
The Land Institute, Salina, KS
http://www.landinstitute.org/
Sustainable Building
Habitat ReStores
http://www.habitat.org/env/restores.aspx
I Love Cob
http://www.ilovecob.com/
Rammed Earth Works
http://www.rammedearthworks.com/
Straw Bale Building
http://strawbale.com/
Sustainable Economics
Redefining Progress
http://www.rprogress.org/
Sustainable Growing and Eating
100 Mile Diet
http://www.100milediet.org/
City Farmer, Vancouver, BC
http://www.cityfarmer.org/
Fairfiew Gardens, Goleta, CA
http://www.fairviewgardens.org/
Farm Aid
http://www.farmaid.org/
Johnny’s Selected Seeds, Winslow, ME
http://www.johnnyseeds.com/
Leopold Center for Sustainable Agriculture, Ames, IA
http://www.leopold.iastate.edu/
Local Harvest
http://www.localharvest.org/
Minnesota Institute for Sustainable Agriculture, St. Paul, MN
http://www.misa.umn.edu/
Nebraska Sustainable Agriculture Society
http://www.nebsusag.org/
Northern Plains Sustainable Agriculture Society
http://www.npsas.org/
Organic Gardening (Rodale)
http://organicgardening.com/
Prairie Moon Nursery, Winona, MN
http://www.prairiemoon.com/
Seed Savers Exchange, Decorah, IA
http://www.seedsavers.org/
Theology
Center for Theology and Land, Dubuque, IA
http://www.ruralministry.com/
Regent College, Vancouver, BC
http://www.regent-college.edu/
Web of Creation
http://www.webofcreation.org/



Another great resource for readers building sustainable gardens is this interactive version of the USDA plant and tree hardiness zone map for South Dakota at:
http://www.plantmaps.com/interactive-south-dakota-usda-plant-zone-hardiness-map.php