Comedy Central is slotted for at least 13 new episodes. Fox reportedly will also have the option of showing them, but most people don't think it's likely.
http://tv.ign.com/articles/714/714479p1.html
A few of the actors have also confirmed in interviews that they were doing new episodes. This was confirmed a couple of years ago, but it's about a two year lag for cartoon shows, so it's supposed to be aired this year.
Dave