It's actually quite straightforward, and only a little more complicated compared to how solar power works.
At a basic level, a wind turbine generates electricity by transferring wind energy into kinetic energy in your blades - this kinetic energy then rotates magnets around a conductor, which generates electricity.
Let's go through it step-by-step:
WIND: The wind itself is moving at least several miles per hour, which means it's carrying energy.
ROTOR BLADES: When the wind hits your blades, it causes them to rotate and it therefore turns into kinetic energy stored in the blades as they move.
SHAFT/TOWER: When the blades rotate, they cause the tower that you have used to mount everything on to rotate, which transfers mechanical energy into your generator - the DC power motor if you've followed my recommendations for building your own wind turbine.
GENERATOR: Inside the generator are sets of magnets located around a conductor in the center. The rotation of your tower causes these magnets to also rotate around the conductor, which means that the magnetic field around the conductor is constantly changing - and that generates electricity.
If you're wondering why a rotating magnetic field generates electricity, you should review Faraday's Law on Wikipedia, which states that an electric current can produce a magnetic field and vice versa since the two are intimately linked.
So, how much electricity can you generate from your own wind turbine?
It's greatly dependent on the materials you use, how well your blades are constructed, and, of course, the average wind speeds near your home.
On average, if you have a wind turbine with 3 blades about 6 feet long and wind speeds of around 20 mph on average, your wind turbine might produce anywhere from 300 to 500 Watts of power.
That alone will significantly cut your electric bill - but if you want to completely eliminate it, you'll probably need at least 5-6 wind turbines so you can generate several kilowatts of power.
Origin: altenergyprograms.blogspot.com
