We reported back in June that Sam Raimi had signed onto direct the movie, which will apparently get started sooner than originally thought. Production will start sometime next year, and Oz: The Great and Powerful will definitely be Sam Raimi's next project. The director is also attached to Warcraft: The Rise of The Lich King, but it looks like that movie is being put on hold until Oz: The Great and Powerful is completed.
Robert Downey Jr. is still not officially attached to star as the title character, although it was said that, "it's looking good" for the actor to join the project. Robert Downey Jr. had previously turned down the role, but it appears he has warmed to Oz: The Great and Powerful with Sam Raimi's involvement.
The movie, which was originally written by Mitchell Kapner, is said to take an early look at the Wizard, a circus wrangler who gets mysteriously transported to Oz via tornado.