NEW YORK (AdAge.com) -- Next week, the ad sales presidents at the broadcast networks will begin the race to lock down advertisers' dollars for next season. What's the prize? The biggest piece they can grab of the $18 billion marketers are prepared to spend on TV. Advertising Age's Claire Atkinson had a chance to speak with each of the key players. Here, she talks to Keith Turner, president-sales and marketing, NBC Universal, about plans to sell his network's digital extensions, dubbed "TV 360," getting the NFL and where his rates will fall this year.