Director James Cameron has signed Joe Letteri and Weta Digital to create the visual effects, creatures and digital environments for his new film "Avatar" for 20th Century Fox. Letteri is a three-time Oscar winner, along with his Wellington, N.Z.-based team, for "The Lord of the Rings: The Two Towers," "The Lord of the Rings: The Return of the King" and "King Kong." "Weta has proven themselves a leader in visionary effects, especially in the area of performance capture based character animation, which is a big part of my new film," Cameron said.