According to a news post on Vulture, Katey 'Leela' Sagal said that
The article however goes on to note that it might be too soon to proclaim the return of Futurama.
"Futurama just got ordered again for another season."
"... insiders from both camps insist that no formal negotiations have taken place and that no deal is done for a new round of episodes."
With past renewals, the voice actors were seemingly contacted just before negotiations commenced or at the very beginning of negotiations to make sure that they'd be available for the show. This has caused confusion regarding the status of the show before.
If there haven't been any official negotiations yet, they'd probably have to start rather soon if Comedy Central wants the episodes to be ready for summer 2012.
Thanks to Andrew for pointing us to Vulture.