Again, bear in mind we can't confirm the information.
As we have previously heard, Warner Bros. wants a Justice League movie. WB Studio President Jeff Robinov has said so himself, and even stated a 2013 release date.
It has even been said that Christopher Nolan will be brought on to produce, that there will be a new Batman, possibly even a new Superman and Green Lantern (as Ryan Reynolds has denied anything JL related).
However, it appears there has been some recent discussion at Warner Bros. in regards to the direction of the movie.
Plans are being put together for Justice League movie for either a 2015 or 2016 release.
DC Entertainment will be spearheading the film, and it will be distributed by Warner Bros. and Legendary Pictures.
Geoff Johns, DC Comics Chief Creative Officer and Co-Producer on the Green Lantern movie, will be on the Justice League movie as an Executive Producer, and will be doing the initial treatment for the film before a writer is brought on to pen the screenplay.
David Goyer (screenwriter on Man of Steel) is said to be the initial favorite for the screenplay.
As Johns hasn't started work on the treatment yet, story details will not be made known, just production details within the next few months as to what it will hold.
The reason for the later release date is to get the movie right and do it proper.
They want Christopher Nolan and wife, Emma Thomas, to be involved in the film in some capacity, most likely as producers. Don't expect Christian Bale as Batman; it will be a new actor in the role.
However, Henry Cavill and Ryan Reynolds could appear as their respective characters, Superman and Green Lantern -- but it is too early to tell.
There is a strong indication that the Justice League movie will be part of a shared universe.
WB wants another Superman movie released before Justice League; however, don't expect that story to be compromised for Justice League, as the next Superman film will still be treated as a stand alone film.
Another Green Lantern film before Justice League is also a possibility. It's being said the Green Lantern sequel will definitely be better than the first as Sinestro will be the villain, and also that the sequel will act as the first step towards a joint universe in which hints towards other heroes can be integrated more easily (than lets say a Superman sequel).