PLS have recently been enabled on the wireless networks of Sprint Nextel and Verizon Wireless. The functionality is offered via the branded ‘virtual networks’ of Disney Mobile and Helio, a new youth-oriented service.

Called the "Buddy Beacon," Helio’s PLS enables users of Samsung Drift handsets to build a "buddy list" that broadcasts locations to self-selected members for display on GPS-linked maps.

"Helio’s Buddy Beacon is going to be very popular," said ABI Research analyst Ken Hyers. "It’s innovative. This is the first service of its kind in North America."

However, Mr. Hyers warns that there are possible downsides. "Users must remember that they can switch the function on and off, and should manage their buddy lists prudently. The service concept is strong, but people who use it must be aware of the ’stalkerware’ implications," he said. "It’s a major reason why operators have been so cautious about how they implement ‘family-finder’ services."