While we don't have an official confirmation yet that Kristen has signed up for the project, it looks like its a done deal. DeadLine has mentined her as part of the cast, which is a really good sign. We might as well just wait for the official announcement.
Also gearing up for production starts are rival Snow White pictures The Brothers Grimm: Snow White from Relativity Media that has Julia Roberts starring, and Snow White and the Huntsman from Universal Pictures, with Kristen Stewart, Michael Fassbender and Charlize Theron starring.
Julia's project is a closer adaptation to the story by the Brothers Grimm, and Kristen’s project is a new take on the story which features action, love triangles and a touch of horror.