Tickets for "Twilight" movies, depending on the theater, might go on sale up to a month or more before opening night. Pick out your theater, and start inquiring with management two months before opening night. Bookmark the theater's website and watch for announcements about pre-sales.
Most theaters sell tickets through sites such as Fandango, Movie Tickets or Moviefone. However, those sites charge an extra fee per ticket. Figure out whether you want to pay for the convenience of purchasing the ticket at your computer or if you want to save money by going to the theater to buy them. If you have a large group (which "Twi-hards," a name for "Twilight" fans, tend to be) drive to the theater to buy several tickets at once.
The first three "Twilight" movies made a collected average of over $90 million on their opening weekends. That's a lot of tickets. Be prepared for large crowds and long lines before the movie begins.