Holmdel, N.J.—Telecommunications company Vonage Holdings Corp. has selected JWT New York as its creative agency of record and Horizon Media, New York, as its media agency, following a review. TBWA/Chiat/Day, New York, previously handled creative, and PHD, New York, was the previous media agency. Both agencies will begin their assignments on March 1. Billings are estimated at $150 million.