Up until now, parents had to deal with a separate company or buy special equipment to track their children through their cell phones. Sprint Nextel Corp. (S) becomes the first U.S. wireless provider to sell its own product when the Family Locator Service rolls out Thursday.

Using the Global Positioning System, the service allows parents to track up to four cell phones over the Internet or on their own wireless device. Parents can periodically ask the service to find the child's phone, displaying the location on a road map.

Parents can also set alerts, automatically warning the parent if the child isn't at a certain place, such as school or soccer practice, at a specific time.

The child's phone also displays a text message, letting the child know they've been searched for and found.

The software, provided through WaveMarket Inc. for $9.99 per month, can be downloaded on 17 existing phones and can locate 28 GPS-enabled models.

Sprint officials insist their service isn't a "Big Brother" tool.

"It's not about tracking. It's not about monitoring," said Dan Gilmartin, Sprint's marketing manager for location-based services. "It's about giving parents and caregivers peace of mind that they're able to find their children's location."

He added that the service could let adults keep track of elderly parents.

The demand for child-locating products is heating up, with several third-party providers, such as Wherify and Teen Arrive Alive, already selling location services.

Last week, CATS Communication Inc. said it was releasing a service to warn parents if their child went near the home of a registered sex offender, and The Walt Disney Co.(DIS) is targeting children this summer with a GPS-enabled phone that includes a locating feature.