Mobile-using parents want to track their kids by phone.

New revenue streams may be headed to mobile operators, according to the TruePosition-sponsored "Opportunities for Location Based Services in Consumer and Enterprise Markets” study, conducted by IDC.

IDC found that one-half of US adults surveyed preferred ad-supported location-based mobile search, instead of paying fees for such services.

“Consumers are grasping the concept of location-based services, and they have very specific ideas about how they should work," said Robert Morrison, senior vice president of TruePosition, in a statement.

Location-Based Mobile Search Pricing Model Preferred by Adult Consumers in Spain, the UK and the US, 2007 (% of respondents)

The combination of GPS or other locator services with local search holds promise for marketers, but even early adopters will have high expectations.

Besides getting advertisers to pay for location-based mobile search, respondents in the IDC study said they wanted the services to work anywhere in the country, including dense metropolitan areas.

Respondents were also concerned about security. IDC said consumers overall wanted to restrict such services to authorized users, and a process to keep out strangers.

With those requirements met, more than one-third of respondents said they were likely or very likely to subscribe to child-locator services in the next 12 months.

In a good sign for location-based services, most US mobile Internet users are interested in task-oriented content, according to an iCrossing study. Users picked maps, weather, local information and news above entertainment and sports as the content categories they searched.

Content Categories Searched by US Mobile Search Users, March 2007 (% of respondents)