Wind power uses the energy produced by moving air to generate power. 
It is actually a form of solar energy.  The sun heats the Earth’s surface unevenly creating areas of differing pressures, producing wind.  Through the use of wind turbines, the energy produced can be converted and used as a clean source of electricity. 

Wind Turbines can be used on a large or small scale.  Large turbines are typically arranged on ‘Wind Farms’ where the average wind exposure is higher.  Small wind turbines can also be used in areas with modest wind exposure and speed for use in homes or businesses, potentially lowering the monthly electric bill.  According to the American Wind Energy Association (http://www.awea.org/pubs/factsheets/Wind), one third of the U.S. has enough wind to generate electricity economically.

The turbine itself is the mechanical opposite of a fan.  A fan uses electricity to produce wind.  In a turbine, the wind turns the blades which spin a shaft connected to a generator, making electricity. 

As a renewable energy source, wind power leaves a smaller footprint on the environment. Compared to other energy resources, wind power stands out because it lacks both air pollutants and greenhouse gases.  When compared to the use of coal, nuclear power and dams, wind power has a small impact on wildlife and the natural surroundings.

http://www.awea.org  information retrieved on 7/19/2007
http://www.bergey.com information retrieved on 7/19/2007
http://www1.eere.energy.gov information retrieved on 7/19/2007