Many people don't realize that you don't have to install your own Windmill or Hydro plant to use Green Energy. Buying green energy is usually as simple as filling out a form, and mailing it in. Your current power company will then pay the Green power company instead of themselves for the power. You will usualy end up paying a few cents extra per Kwh, but for the average home it doesn't typically amount to much extra.
Use the US Department of Energy's Green Power Buying Guide to find out how to sign up in your state.