A new add-on for Electronic Arts' smash PC game "The Sims" was the top-selling PC game in September, according to sales rankings released Thursday by researcher NPD Funworld. "The Sims: Unleashed" was No. 1, followed by EA's new online war game "Battlefield 1942." Other new titles on the list included Infogrames' shooting game "Unreal Tournament 2003," at No. 4, and Take-Two's organized-crime romp "Mafia," at No. 9.