3-D, of course.
The rumors of the sacred trilogy(as well as the putrid prequels) being re-released using the format have been around for at least a couple of years, but the technology standard as well the lack of 3-D screens were a holdup. Obviously that's not the case anymore.
THR and Deadline both confirm that the films will be released starting in 2012 at the rate of one per year. They will be released in chronological order so The Phantom Menace would be first in line. Personally, I don't much see the point. By the time I get through the prequel flicks I will have long since poked my eyes out with a sharpened pencil lead. We can expect the whole thing to wrap up with Return of the Jedi(3-D Ewoks!!) in 2017. Even in 3-D those little teddy ruxpin lookin' bastards shouldn't win.
The post-conversion process is said to take up to a year for each flick. Considering Clash of the Titans