There will now be only one "fifth network." In an unexpected announcement CBS Corp. and Warner Bros. Entertainment/Tribune Broadcasting said today (Tuesday) that they will merge UPN and The WB networks into a new broadcast network, the CW Television Network. UPN President Dawn Ostroff will become President of Entertainment of the new network, while John Matta, currently COO of The WB will become its COO. Timing of the merger was not immediately disclosed.