The Fables convention in Rochester, MN is over now, and people who visited the Saturday panel got a first look at Telltale's Fables game.
The rest of us will get a look at the game when Telltale has their official reveal on Wednesday. But, until then The LA Times has an article about the Fables convention that has some information about the game:
“Fables” fans also got to see their favorite winged monkey librarian take flight Saturday during Telltale Games’ preview of the upcoming video game set in the comic’s world. The title won’t be announced until Wednesday, but Telltale’s Richard Iggo said gamers would play as Bigby Wolf, that there would be new characters and that the story is set before Issue 1 of the series. He said players will feel the “narrative clock ticking” in the game, and that outcomes are not determined only by choices, but also by the timing of those choices.
“We’ve always strived to see the players of our games … as the last collaborator in the creation of the story,” he said.
Willingham said the game is canon, and there are ideas Telltale originated that he wants to “steal” for future “Fables” issues.