MIT Study "The Future of Geothermal Energy":
http://www1.eere.energy.gov/geothermal/future_geothermal.html

U.S. Department of Energy (Geothermal Energy Technical Site):
http://geothermal.id.doe.gov

U.S. Department of Energy (Geothermal Technologies Program)
http://www.eere.energy.gov/geothermal

U.S. Department of Energy (GeoPowering the West)
http://www.eere.energy.gov/geothermal/deployment_gpw.html

Sandia National Laboratories (Geothermal Research Department)
https://cfwebprod.sandia.gov/cfdocs/GPI/

Energy Quest - California Energy Commission
http://www.energyquest.ca.gov

Energy Information Administration
http://www.eia.doe.gov/kids
GeoHeat Center (Low Temperature Uses of Geothermal Water and Heat):
http://geoheat.oit.edu

International Ground Source Heat Pump Association (Geothermal Heat Pumps):
http://www.igshpa.okstate.edu

International Geothermal Association
http://iga.igg.cnr.it/index.php

Geothermal Resources Council (Geothermal Industry Association):
http://www.geothermal.org

Geothermal Energy Association (Industry Trade Association):
http://www.geo-energy.org

Geothermal Heat Pump Consortium
http://www.geoexchange.org

California Department of Conservation, Department of Oil, Gas and Geothermal Resources:
http://www.consrv.ca.gov/DOG/geothermal

California Energy Commission (Geothermal Energy):
http://www.energy.ca.gov/geothermal

Center for Renewable Energy and Sustainable Energy Technologies (CREST):
http://www.crest.org

Southern Methodist University (Geothermal Lab)
http://www.smu.edu/geothermal

Underwater Voyage to Puna Ridge
http://www.punaridge.org

U.S. Geological Survey (plate tectonics)
http://geology.er.usgs.gov/eastern/tectonic.html
World Bank Group (general info)
http://www.worldbank.org/html/fpd/energy/geothermal

GeoResearch:

Drilling & Instrumentation Research:
David Glowka, Sandia National Laboratory
daglowk@sandia.gov

Exploration Research
Paul Kasameyer, Lawrence Livermore National Laboratory
kasameyer1@llnl.gov

Reservoir & Exploration Research
Marcelo Lippmann, Lawrence Berkeley National Laboratory
mjlippmann@lbl.gov

Exploration & Reservoir Research
Joel Renner, Idaho National Engineering Laboratory
http://geothermal.id.doe.gov