Nearly 30 years after “Star Wars” first hit Iowa’s movie screens, the final installment in the six-film saga is hours away from its premiere. Mike Catrenich manages a Des Moines theatre where several hundred fans of the Force were already lined up when he came in to work this morning. Some were dressed as characters from the movie, like stormtroopers or Obiwan Kenobi. He says some 300 people are in the parking garage and are sitting down and playing games.Catrenich has already watched “Revenge of the Sith” and with the stunning light saber battle in lava. He says the movie explains why Darth Vader went to the “dark side” and ties the other five movies together. Catrenich’s theatre has featured many of the Star Wars films and says the fans are extremely loyal. Catrenich manages Merle Hay Cinemas which boasts Iowa’s largest screen and 800 seats, all of which he expects to be filled for the debut of “Episode Three” — the last so-called prequel of the series. Most screenings start at one-past midnight so he jokes plenty of Iowans will be calling in sick tomorrow with Skywalker-itis. Many Iowa theaters, from Sioux City to Cedar Rapids to Davenport, report sell-outs for the first overnight showings.