While Jajah has a potential market in families whose members are distributed across the globe, "you have to spend a lot of money to market your service, and I'd doubt that there is sufficient revenue potential for Jajah to overcome the marketing costs," said Irwin Lazar, a principal analyst with Nemertes Research.

Still, he expects VOIP companies to battle mightily over mobile users over the next two or three years, potentially leading to the slaying of a big dragon -- per-minute billing for mobile calls.