Sounds like 30 Days of Night: II

Myriad Pictures and comic book publisher Studio 407 are joining forces to produce a feature film version of the indie comic book miniseries The Night Projectionist. The story takes place on Halloween Eve in the town of Crosstown Falls, where a bunch of unlucky film-goers are enjoying an all-night Dracula-themed film festival. Unfortunately for them, the projectionist is (shocker!) a vampire, and he's planning on celebrating his holiday with a locked-down theater's worth of yummy human munchies....

I have no idea when the movie will be out (but smart money's on October 30th), but the first issue of "The Night Projectionist" miniseries will hit shelves in February, and you can view an 8-page-long preview here.