All I can say is, wow... They have less than a year to get the movie written, produced, edited and visual effects completed. Talk about a rush job.
There haven't been any indications that a script has been written yet, and no doubt writer/director Weitz will have a hand in writing (or re-writing it, if there's already one done). That takes more time, as do any script revisions, and I'm betting the quality will suffer.
There have also been rumors that Summit may try to save money and shoot New Moon and a movie based on the third book in the series, Eclipse, back-to-back. That would mean another screenplay needs to be written quickly, so they can start shooting both films by the Spring at the latest. Pounding out one screenplay in a short period of time is, to be honest, never a good thing. Add a second movie, and it spells potential disaster.
My gut feeling is that they won't shoot New Moon and Eclipse back-to-back, but instead will focus only on the second film. The cast, featuring Robert Pattinson and Kristen Stewart, will return for the sequel, so you can rest easy, Twilight fans! Let's hope they don't rush New Moon too much, which could lead to a bad film.
Source: Box Office Mojo