JOHANNESBURG, South Africa -- It is Friday evening, and dozen Mercedes-Benzes and BMWs are parked across the street from The Rock nightclub. The crowd sports designer clothes and haircuts. Buckets of champagne top the tables, and patrons, three-deep at sleek, silver-topped bar, wave cash to buy another round. The ritzy nightspot isn't in Los Angeles or London. It is in Soweto, a sprawling community on the outskirts of Johannesburg and a place once synonymous with extreme poverty and brutality of white rule. Home to roughly a million people, Soweto now is sprouting nightclubs, shopping malls and modern bank branches. Roads,...