People like Ms. Skhakhane have made Africa the world's fastest-growing cellphone market. From 1999 through 2004, the number of mobile subscribers in Africa jumped to 76.8 million, from 7.5 million, an average annual increase of 58 percent. South Africa, the continent's richest nation, accounted for one-fifth of that growth.

Asia, the next fastest-expanding market, grew by an annual average of just 34 percent in that period.