I don't think so, either. They announced this movie in response to the good DVD sales, and it was intended to be a straight-to-DVD release. But I haven't heard any updates since they announced they were bringing the series itself back outright.
I could have sworn I read somewhere that production had started.
From what I gathered they were having the cast tape their voice work from where ever they happened to be that way they could work around their schedules.
Anybody know if Mila Kunis is going to come back as the voice of Meg?