You want to see where that annoying phone call comes from? Do you want to trace where a particular caller really is ? Try this.
GSM mobile phone tracking system via the GPS-TRACK satellite network
Approximate margin of error:
10 meters (max.) for mobile phones in Europe and the U.K.
25 meters (max.) for mobile phones in the U.S.A., South America and Canada.
50 meters (max.) for mobile phones elsewhere.
This system will not work in countries without GSM technology networks.