In an article about how actress Gloria Stuart, who played the elderly Rose in "Titanic," who is turning 100-years-old, the Los Angeles Times mentioned that director James Cameron is converting "Titanic" to 3D for a re-release in April of 2012.
Cameron has always stated that shooting a movie with 3D cameras is superior to converting it to 3D in post-production. In fact, he has gone on to completely trash the conversion process, but there he is working on "Titanic 3D" and possibly "Terminator 2 3D."
Cameron is not the only one who is converting movies to 3D. Peter Jackson recently revealed that he is working on re-releasing the "Lord of the Rings" trilogy in 3D, and Christopher Nolan said that he will likely convert "Batman 3" to 3D as well.