The new WB animated movie, Justice League: The Flashpoint Paradox, has a July 30, 2013 release.
In addition, it has also become known that Kevin Conroy will return to voice the role of Batman and will play Bruce Wayne in the regular DC universe aspects of the film.
Ron Perlman will also be back as Slade Wilson and Deathstroke with Dana Delany voicing Lois Lane, and Vanessa Marshall as Wonder Woman.
The actors for The Flash, Cyborg, Reverse Flash, Aquaman, and Thomas Wayne/Batman are said to be revealed soon.
Justice League: The Flashpoint Paradox is based on the DC Comics mini-series from Geoff Johns and Andy Kubert that launched the New 52 DC Comics universe.
Newsarama has the official blurb for the movie:
When time travel allows a past wrong to be righted for The Flash and his family, the ripples of the event prove disastrous as a fractured, alternate reality now exists where a Justice League never formed, and even Superman is nowhere to be found. Teaming with a grittier, more violent Dark Knight and Cyborg, Flash races to restore the continuity of his original timeline while this new world is ravaged by a fierce war between Wonder Woman's Amazons and Aquaman’s Atlanteans. With breath taking action and an all-star voice cast, it's a bold, emotional vision that will forever change the landscape of the DC Universe.