Phonon dispersions for helical s(2/l)2 syndiotactic polystyrene (sPS) are obtained and compared with the dispersions for its planar form. Optically active frequencies corresponding to the zone center and zone boundary are identified and discussed. In general the dispersion in the helical form is less as compared to the planar form. Some of the distinguishing features such as crossing over, repulsion of modes, and profile of the acoustic modes are discussed and possible explanations are given.