There's even more at the link below.
The series is set between the events of Episode III and IV -- an era spanning almost two decades never-before explored on-screen. It takes place in a time where the Empire is securing its grip on the galaxy and hunting down the last of the Jedi Knights as a fledgling rebellion against the Empire is taking shape.
Star Wars Rebels will be produced by Lucasfilm Animation, featuring many of the key talents that made Star Wars: The Clone Wars. It is scheduled to premiere in fall 2014 as a one-hour special telecast on Disney Channel, and will be followed by a series on Disney XD channels around the world.