Seeing so many wind farms in western Oklahoma, which has slightly marginal winds for that purpose, makes me wonder about the states further west and north. Probably it's a matter of transmission lines. The farms will tend to spring up along the lines.
I surfed the web. FYI, here's the wikipedia entry: http://en.wikipedia.org/wiki/Wind_turbine . I guess I'll have to start calling them wind turbines. Hmm. Nope, they're still windmills.
Edit: See what T. Boone Pickens says about wind power: http://www.pickensplan.com/index.php