During a Warner Bros. panel at 2013 San Diego Comic-Con International, Warner Bros. will be announcing a Justice League movie for 2017, according to The Hollywood Reporter.
Rumors of a Justice League movie have been circulating for quite some time, but most previous rumors had set the release date as 2015. While Christopher Nolan's Dark Knight trilogy was set in its own universe, the Man Of Steel movie was specifically developed to be the first step in assembling a Justice League.
The Justice League first appeared in The Brave and the Bold #28 back in February/March 1960. The initial Justice League lineup included Superman, Batman, Aquaman, Flash, Green Lantern, Martian Manhunter, and Wonder Woman. The current members of the core Justice League in the New 52 version of the DC Universe include Superman, Batman, Wonder Woman, Aquaman, Green Lantern, Flash, and Cyborg.