Apps that Track Stolen Smartphones Are Pretty Worthless...
There are dozens of mobile apps out there designed to let you track your phone if it's ever lost or stolen. The best of these are Prey (for Android smartphones), LoJack (for laptops), and Find My iPhone (for iPhones, obviously).
They tend to be great for when you accidentally lose your phone in the deep recesses of your couch cushions. However, when your phone is actually stolen, these apps are pretty worthless - despite how they're marketed.
When my father recently had his iPhone stolen - from his hospital bed, no less - he used the "Find My iPhone" app within a short time from when it must have been taken. Sure enough, the app worked marvelously. It displayed the exact location of the phone at that very moment - at a specific intersection in Queens. He was very excited at the prospect that the app might actually lead to the phone's recovery.
But when he called the police, they informed him there was little they could do about it. You see, despite knowing the exact location of your stolen property, before the authorities can legally act, you still have to file an official police report; hopefully that leads to a subpoena being sent to the IP addresses' internet service provider; and only then can the police search the exact location specified in the subpoena. This process takes days or even weeks, and as a result, it's unlikely the phone will still be found at the same intersection in Queens.
The lesson of the story is that these "tracking apps" do work, but the law is far behind the technology. So short of tracking your phone's location down personally and confronting the thief face-to-face (which is highly unrecommended), understand these apps' gross limitations.