With new voices from what I hear. They didn't want to anty up to bring the old cast back, so they scrapped them all..
http://www.thestar.com/entertainment/article/674841 The original cast is going to still be doing the voices. "The compromise agreement, with the studio paying more and the actors accepting less, comes after the announcement of a 26-episode pick-up here by Comedy Central. Futurama also airs internationally in syndication, has produced four bestselling straight-to-DVD movies (later cut into episodes) and an upcoming feature film"
http://popwatch.ew.com/2009/07/17/futurama-new-voices/ That's the first link that popped up. It was widely discussed about a year ago. Maybe they got it resolved? That's the last I'd heard of it though.
Yes it was resolved. Just your typical negotiation ploy, they do it all the time whenever the Simpsons actors ask for more money. All the original voice actors are back, no need to worry.