Wind turbines capture kinetic energy from the wind, converting it to electricity by using a reduction gear to take the slow moving fan blades to run a fast generator in the center, which then delivers electricity to the house. If your utility uses net metering, any excess electricity you generate is credited against your bill - indeed, in some months, the local electric "bill" is a check because you gave them more electricity than you used. Most turbine companies will send a crew out to set up the turbine, and help you fill out the paperwork with your utility.
The primary benefit, from an engineering standpoint, of home wind power generators is that they eliminate the overhead caused by transmission line power losses. While an individual wind power generator isn't as efficient as an individual coal fired burner on a BTUs to kilowatts basis, the reduction in transformer and power line losses makes up for it. In terms of carbon offsets, for a typical household use, a wind power generator offsets about 1.2 tons of sulfates and nearly 200 tons of CO2.
A typical wind power turbine costs about 12,000, with larger ones going to 20,000 and will last for 20 years. Dividing even a high end one by 240 months (20 years times 12 months) will give a per month cost of around 85; the question becomes "Will it save you more than 85/month in electricity bills?" And the answer to that is dependant on your location and local zoning ordnances. Fortunately, wind turbines are very low maintenance, and as demand for them rises, prices are coming down. There are models for as low as 6,000 available now.
It's an open matter as to whether or not a "wind power generator" increases your property's resale value. In some markets, where green consciousness is high, it is - in others, where having a giant fan sticking out of the backyard is considered an eyesore, or blocks line of sight for the neighbors, it's definitely not - talk to your local community advocacy groups to get the lay of local opinion before installing one.
