I don't believe there's an official website yet. Try a search on Google for "dragonball live-action", or look here:

http://members.fortunecity.com/dbzmovie/

The director is Roland Emmerich (Independence Day, Godzilla, etc.), so it's definitely being handled by someone who knows how to blow things up good. I'm personally trying to start an unfounded rumour that Hugh Jackman will be replaced by Charlie Sheen for the role of Goku.