It's not clear if we'll hear the sounds of festive celebration or the screams of the torturous murder come the strike of midnight. The radio station teases you to "Come down to the Cashmere Restaurant at midnight, where the rich and beautiful will dance their cares away!" Given the history of Rapture, that doesn't seem likely. In the meantime, tune in here via iTunes or Winamp, or here for the Windows Media Player flavor.
UPDATE: You can listen to the audio of the party below. It's all hubbub and rhubarb until 09:14, then all hell breaks lose. The station now just plays static, and a random message that they're experiencing problems. "There has been an incident at the Cashmere (Kashmir?) Restaurant. Please return to the safety of your homes."
UPDATE TO THE UPDATE: Here's the emergency incident message as well.