Swisscom just published an app called CheckAp to help you understand your exposure on your phone. It helps you to look at what the different apps want to access on your phone like GPS, camera, contacts etc. Basically you can get the same kind of information in the app stores. However, depending on the platform you are on, this information is more or less reliable.
The Swisscom app is sourced by a third-party (in the US), which checks the apps and rates them accordingly. It is available on the iPhone and on Android, but the scanner (showing you the list of your apps) is only available on Android as it seems to be impossible to get a list of installed apps on the iPhone.
I saw some chatter in the Swiss press about how useful such an app is. Even if you challenge the rating an app on your phone got, it can increase the awareness of users that apps might not only do what you want them to.