Reportedly a loose adaptation of the Mark Waid series, "JLA: Tower of Babel", the animated film Justice League: Doom was adapted and written by Dwayne McDuffie right before his death in February 2011, and is directed by Lauren Montgomery, according to ComicBookmovie.com. It is set to be released in early 2012.
Justice League: Doom features the voices of many talented actors, including Carl Lumbly (M.A.N.T.I.S., Alias), Phil Morris (Star Trek: Deep Space Nine, Seinfeld, Smallville) and Bumper Robinson (Amen, The Old Settler), just to name a few.
Lumbly will voice the character of Martian Manhunter; Morris will voice the character of Vandal Savage; and Robinson will be heard as the voice of Cyborg.
Check out the trailer:
And also check these supposedly leaked clips: