These would presumably be the non-Saga origin stories that have been talked about before as part of the overall Star Wars plan to release one film per year, alternating between trilogy and non-trilogy. With Star Wars: Episode VII opening in December 2015, that would seem to indicate the first spinoff would be in 2016. Han Solo, Yoda, and Boba Fett are the characters that have been mentioned as possibly getting their own solo spinoff films but nothing is confirmed at this stage.
Simon Kinberg and Lawrence Kasdan are attached to these projects, and maybe we'll get more info on them at Comic-Con this summer.
