Leap Wireless has broken into the urban youth scene with a new brand of wireless, prepaid phone service called Jump Mobile. The service is available in select markets, including Phoenix and Tucson, Ariz., Denver, Dayton, Ohio, Memphis, Tenn., and Charlotte and Greensboro, N.C. Distribution will be expanded nationwide in 2006.

Jump Mobile has attitude and customized service the company believes will play well among urban kids. The service includes free unlimited inbound and outbound text messaging, free incoming voice and 10 cents a minute outbound voice calls. Leap turned to Los Angeles youth marketing company Rebel Organization to design the service’s edgy logo and marketing materials.

Leap may be onto something. Boston market research company Yankee Group reports that although 53 percent of American teens now get cellular service through their parents’ family plans, that trend is changing. Yankee predicts prepaid and hybrid payment plans will drive future growth among young adult users. The company says the proportion of teens using prepaid plans rose 8 percentage points from 2004 to 2005 while traditional subscriptions have declined.

But Leap may find its competition slightly stifled following a federal judge’s decision late in October to require Boston Communications Group Inc. to pay an additional $20 million in interest to Freedom Wireless Inc. for infringing on patents of prepaid wireless billing systems. A jury earlier this year awarded the plaintiff $128 million. Yankee Group says the decision “severely hobbled” the development of prepaid cellular phone service and predicts more hobbling is on the way with additional lawsuits against wireless carriers.