When Katey Sagal visited The Late Late Show the other day, she told Craig that the show is coming back to Comedy Central in 2008 for at least 13 episodes (I was watching that appearance, too. Must have slept through that part). Don Kaplan of the New York Post confirmed this; his sources told him that all the primary voice actors signed new deals this week. Also according to the article, FOX may have the option to air the new episodes, but probably won't. The new episodes will also come out on DVD after they air.
There were rumours of this last year, but it's good to see they finally confirmed it!