• by David Goetzl  @dgoetzl, December 18, 2007

Viacom networks The N and Noggin--targeting teens and preschoolers, respectively--will each become a stand-alone 24-hour network as of Dec. 31. The networks have been sharing a single channel space, taking up 12 hours each.

Viacom said The N, known for carrying "Degrassi: The Next Generation," will debut three original and two acquired series in 2008. That slate includes reality show "Queen Bees," which will attempt makeovers of mean girls; scripted comedy "The Assistants," about the trying life of being an assistant for a Hollywood hotshot; and six seasons' worth of episodes from one-time hit "Saved by the Bell."

"Saved by the Bell" episodes begin airing on Jan. 14, with "Queen Bees" and another reality series, hosted by Laila Ali, in the summer. "The Assistants" kicks off next fall. Acquired series "That '70s Show," which gave Ashton Kutcher his big break, premieres in June.

Noggin will remain commercial-free when it goes round-the-clock. It makes its stand-alone debut with "a movie marathon" on New Year's Eve that includes the "Dora the Explorer" TV film.

As its own network, Noggin will debut a new fall show "Toot & Puddle," a 26-episode animated series based on a popular children's book series.

Noggin general manager Brown Johnson said: "Noggin's expansion into a 24-hour network reinforces Nickelodeon's commitment to preschoolers and their caregivers, to be there whenever they need us."

"The N going 24 is a great opportunity to provide around-the-clock teen programming to our growing audience, as we continue to roll out new series, specials and acquisitions," said Sarah Tomassi Lindman, general manager of The N. "The network's distinct perspective that reflects the teen experience will now be available anytime and everywhere."