I’m a member of the International Dark-Sky Association. These guys are the light pollution authorities of the world. If you visit their website, you can find all kinds of information about the importance of dark skies (and not just to astronomers), as well as how to make your block, your community, your city, your state, a dark-sky site. They have a link to lighting practices and equipment that will help preserve dark skies while maintaining safety in your community. And, many of their suggestions help preserve energy expenses (an important factor).
The community I live in has some energy- and light-pollution-cutting lighting practices, although some neighbors still think it’s great to throw light up to the sky indiscriminately. In our neighborhood we managed to get our local utility to put up “screens” around the nearest streetlight so that the light shines down on the street, like it’s supposed to, and not in our bedroom window, or bathing our yard.
One of the more illustrative pages on their site is a series of links to various places on Earth, showing the light pollution from satellite’s-eye views. Check it out, and do your part to reduce light pollution, save energy, and preserve the beauty of the night skies for everyone to appreciate.