Is Narnia 3rd Movie being made?

Does anyone know if theres a 3rd Narnia movie being made? I just saw Prince Caspian and the movie is good. I also saw the 1st one awhile back and I'm getting hooked to the movies. I should start reading the books soon. Any way, does anyone have any information when the 3rd movie will be coming out? Or are they already working on it or not?