ATTENTION ALL MUGGLES! Director Chris Columbus and producer David Heyman have discovered their Harry Potter, Ron Weasley and Hermione Granger from the thousands of children who cast their names into the hat to play the roles. Young actor Daniel Radcliffe will be the film's Harry, with newcomers Rupert Grint and Emma Watson taking on the roles of Ron and Hermione, Harry's best friends at Hogwarts, in Warner Bros. Pictures' upcoming adaptation of the first in the best-selling series of Harry Potter books by J.K. Rowling.