There is a program called Vue made by e-on software that allows you to create landscapes fairly easily. I am new to it and have only just touched the surface, but with my little knowledge and the help of a tutorial from this site http://vimeo.com/groups/19298/videos/6891644 I was able to make something. My hopes are to learn this well enough to use along side maya as a tool to create scenes that involve the outdoors.