The following list is a sumary of all the info get from DBZ Live Movie Unofficial Forum: The movie will start since the beggining (when Goku meet Bulma), focusing especial atention in Goku (a teenager), Bulma (a girl in the college), Yamcha (who is around his mid-twenties) and Roshi. The main villain will be Piccolo (a complete badass), and King Pilaf will play an important rol in the movie.
Supossely, the movie will start in our real world, especifically in New York City, but when Piccolo shows up the whole world will shift to the Dragon Ball world and, as in the anime, Piccolo is kept away in the small shrine during 1000 years, when finally he awake (and the movie start).
The official casting process isn't started yet, but the director and the actors probably will be "known faces with good acting abilities, perfecto for the roles and phisically similar to the characters". But has official conversations with Bill Goldberg (Universal Soldier: The Return; Looney Tunes: Back in the action), Tom Welling (Smallville; Cheaper by the Dozen) and Ray Park (Star Wars: Episode 1 - The Phantom Menace; X-Men)
Ben Ransey finished the scrip months ago, then the FOX read it and like it,but everyone is waiting for Gianapolis' approvation (the guy head of FOX).
Ransey don't want CGI characters in the movie: Apparently Puar will be just a mischievous cat and Ooling will be different to the anime.
The movie is scheduled to 2007. After the end of Star War in 2005, FOX plans to introduce Dragon Ball as a franchise of, minimun, 5 movies (4 hours for movie). The first 2 movies will be filmed between Mexico and US, in The Lord Of The Rings style. And as will be more than one movie, it will have a subtitle, like Dragon Ball: Saiyan Invasions or Dragon Ball: Unlimited