Rihanna, Ludacris and K.T. Tunstall will join Xtina, Rascal Flatts and the cast of Jersey Boys as musical guests on Dick Clark's New Year's Rockin' Eve 2007. Over on the Peacock, meanwhile, NBC's New Year's Eve with Carson Daly has booked Panic! at the Disco (Matt. Feeling. So. Old.) to perform live from Times Square.