Harvesting the wind for energy is not a new concept.  The origins of using the  winds to to produce mechanical energy are lost in the mists of time . Mankind was using wind power to move his ships and grind his grain at least a couple thousand years ago. With the advent of electricity it was only natural to utilise this abundant source of raw power.
  Early wind turbines in the beginning of the 20Th century provided some of the first usable electricity to farms and businesses before the coming of the electric power lines. The designs of this early period are still in production nearly one hundred years later and are a credit to the original engineering.
   One popular method of building a small (approx one hundred watt) system is to use a permanent magnet motor from a treadmill or commercial style Amtek tape drive motor as the generator. This class of motors through much experimentation have been found to be durable, inexpensive and effective used as a small wind generator. Blades are often made from common PVC waist pipe of between six and twelve inches in diameter.
  Larger turbines can be created using a Permanent Magnet Alternator  or PMA and other parts readily fabricated or purchased at any of the many online auction sites.these setups can often produce over one thousand watts in a stiff breeze.
  The smaller permanent magnet class of micro-wind turbines is usually used in remote installations for battery charging. The larger PMA turbines can power whole households or businesses. In many states a grid tied system where excess power is sold back to the electric company is also a possibility. Generally as much money and design must go into the tower that your turbines sits on, as the wind generator itself. safety must always be a primary concern in any installation.
  Many options exist in building ones own wind power system from pre-built units to  built totally from scratch solutions. Prices can range from near free to many thousands of dollars depending on the goals of the project. A rather large Micro-wind power industry has developed recently. A good place to start is to google various wind power related search terms. Careful attention should be paid to issues such as needed power output and power storage. While potentially very rewarding this is not a project to take on lightly and every bit of pre-planning is guaranteed to pay of in the usefulness of your final installation.