Currently in the early stages of developing a second season of The Walking Dead, Telltale are "figuring out how to carry the saves over" so that your decisions in the first five episodes will have a noticeable impact on the new story.
VG247 spotted an interview with Telltale's CEO, Dan Connors, over on Redbull UK, where he talks about the development of the first season of The Walking Dead. There are only a few nuggets of information, such as the news that they're "just starting to form the concept for season two," so we shouldn't get our hopes up that we'll be able to continue the story any time soon.
Also, while they're looking into the possibility of having the first game's saves impact the second's story, the effect may not be a great deal more than a few more dialogue threads or discovering bodies of your original group who didn't get away. This is purely speculation but I would not be surprised if this second season followed a different group of survivors who cross paths with some of those you met in the first season.
Connors did also talk of what series he'd like to work on next, though: "Coming from LucasArts we always felt we could do a great Star Wars story game. We also love the idea of building out a deeper story to a great game franchise, something like Half Life Stories or Halo Stories.”
Steve thoroughly enjoyed Telltale's Series, causing him to write this piece on why it's so compelling and this spoiler-filled piece on its ending, and I named it my Game of the Year in this equally spoiler-filled essay.