Sam Raimi is off to see the Wizard.The Mouse House is in early talks with the “Spider-Man” helmer to direct a prequel to “The Wizard of Oz” called “Oz, the Great and Powerful.” Joe Roth (“Alice in Wonderland”) will produce. “Great and Powerful,” based upon the 1939 classic film, tells the story of a circus wrangler who is transported via tornado to the mysterious land of Oz, where he is mistaken for an all-knowing Wizard. “Iron Man” thesp Robert Downey Jr. has long-been rumored as a possible star, though no casting decisions have been made yet. “Oz” marks the first project for Raimi since he left Sony’s “Spiderman” franchise back in January. Sony nixed the fourth skedded Spidey pic, with Raimi and thesp Tobey MaGuire attached, in order to reboot the series. Marc Webb (“500 Days of Summer”) has since been tapped to helm the younger, revamped Spidey. Disney, meanwhile, is hoping audiences will melt for the “Oz” prequel. After “Alice in Wonderland” grossed $1 billion at the worldwide box office, the Mouse House has been especially eager to get the ball rolling on franchise pics. Studio’s sequel to the 1982 sci-fier “Tron” opens this December while “Toy Story 3″ is expected to dominate the summer B.O., starting Friday. Tim Burton’s “Alice,” the year’s highest-grossing release, helped boost the studio’s profits to $953 million last quarter, up 55% from 2009.