OS X Mountain Lion: About managing Location Services
Location Services allows apps and websites to gather and use information based on the current location of your computer. You have to give your permission before the app or website can use your location data. Your approximate location is determined using information from local Wi-Fi networks, and is collected by Location Services in a manner that doesn’t personally identify you.
Apps that you have allowed to use Location Services appear in the Privacy pane of Security & Privacy preferences. Checkboxes show whether Location Services is turned on or off for an app. If you don’t want to allow Location Services for one or more apps, you can turn it off by deselecting the checkbox next to the app. If you turn Location Services off for an app, you’re prompted to turn it on again the next time that app tries to use your location data.
You can also turn Location Services off altogether by deselecting Enable Location Services in the Privacy pane of Security & Privacy preferences. Even if you disable Location Services, third party applications and websites may still use other ways to determine your location.