Where are energy resources found? Here.

The Energy Balance
Energy Resources Index

Petroleum

American Petroleum Institute
Society of Petroleum Engineers
Information about the Petroleum Reserve

Coal

Some Coal related articles
Another coal article
How much coal would it take to run a light bulb for a year? Find out.

Natural Gas

NaturalGas.org
Energy Information Administration
Wikipedia article on Natural Gas

Nuclear/Uranium

How Stuff works Nuclear power
Nuclear Energy Institute
Nuclear Power

Propane

National Propane Gass Association
Site promoting the use of propane
Wikipedia article on Propane

Biomass

Biomass Program
Biomass Research & Development Initiative
Definition of Biomass

Wind

American Wind Energy Association
Investigating Wind Powergenerators
How to build a windmill

Solar

Solar Electric Power Association
How to Make a Solar Power Generator for Less Than $300
Wikipedia article on solar power plants

Geothermal

Geothermal Energy
More Geothermal Energy
One more on geothermal

Hydroelectric Power

Basic overview of Hydroelectric Power
CalPoly article on Hydroelectricity
California Energy Commission

Some fun links for extra information

JPL, home of the Jet Propulsion Laboratory
So you wanna be a rocket scientist?
US Department of Energy
XcelEnergy
Control your own nuclear powerplant!
Sam Barros' Powerlabs, including RailGun Research