The Warner Bros. film is reported to include Batman, Superman, The Flash, Aquaman, Wonder Woman, Martian Manhunter and the Green Lantern.
According to the site: Warner Bros have hired casting directors Susan Shopmaker (The Holiday, Mean Girls), Michelle Allen (TV's sadly cancelled Dead Like Me) and RDC Casting (The Shipping News) in New York, Vancouver and Toronto, respectively, to cast the Justice League movie.
This is confirmed by the casting information (a.k.a 'breakdowns') site, Showfax, Inc., which lists roles for the film (although membership is required for role details), which are available for audition in the following 3 cities:
If you are an actor and live near any of these cities ... who knows, you may become an on-screen superhero!?!
Justice League of America is anticipated to arrive in theatres in 2009.