The 4400 producer Scott Peters has posted on the USA network's message board to announce that the show is no more.
This is a real shame, as though it was never a massive hit, and had a tendency towards the melodramatic, the show was regarded with great fondness by certain members of the SFX crew (well, Leah and Dave G, anyway - we don't mind standing up to be counted). Also, the last episode ended on a hell of a cliffhanger.
So, it's goodbye to the Heroes-lite series, and it's a shame Leah won't be able to any more "rubbish ability of the week" bits in Spoiler Zone. Thanks to the cast and crew - it was fun while it lasted.