I've known about this feature for several years. Google is a fairly new source of this information. The first one I knew about was;
http://www.anywho.com/
Then I found ;
http://www.411.com/
They each have find features whereby you can find someone by name, address or phone number. Go to either and click the "reverse lookup" or "reverse phone" button. Sometimes if you can't find info on one site, it'll be available on another. I use them before I answer a classified ad just to see if it's within a reasonable distance, then to help me find where I'm going. (Some people give really bad directions.)
411.com uses mapquest to draw a detailed path to your door, anywho.com uses RAND McNALLEY.
I'm sure that Google and these other 2 I mentioned aren't the only ones that make this information easily accessible. About the best you can do is to have your number made unlisted AND private. If your number has been listed in the past you should have it changed before you pay to have it unlisted and marked as private. I can't promise that it won't show up in a search, but it will sure reduce the chances. Try these sites with your own phone number and the numbers of friends who you know are listed, unlisted or private, see what you get.
Personally, I don't mind. As long as I've had a phone number it's been listed, that makes it public record. I'm not hiding from anyone or anything and I'm not afraid of anyone. (At least not yet). and there are some old friends that I would welcome a call or visit from.
I have greater things to worry about at the moment, but some people do need to be more aware and cautious for various reasons. There are a lot of idiots with ill intent out there and you never really know who they might be.
