Embedded Player NPR's Snigdha Prakash reports that Viacom is buying BET Holdings, the owner of the nation's only cable-TV network specifically aimed at African-Americans. Viacom will pay 2.5 billion dollars in stock and take on about 500-million-dollars in debt. The deal announced today allows Viacom to add another choice property to its lineup, which includes the CBS and UPN broadcast networks and the MTV and VH1 cable-TV channels