The 5 million unit sales mark for the PS3 has been reached, in Japan anyway;

As of April 11, Famitsu publisher Enterbrain has revealed that over 5 million PlayStation 3s have been sold in The Land of the Rising Sun. Domestically, the top three selling games for the system are Final Fantasy XIII (1.8 million copies), Metal Gear Solid 4 (706,461 copies) and the recently released Yakuza 4 (526,093 copies)

Source