Here's some links to some FREE 3D modeling, animation and rendering utilities that you can use to create some very professional looking art and animation with your computer. There are also on-line tutorials and message board groups to help you out if you get stuck using them.

Celestia - A real-time space simulation that lets you experience our universe in three dimensions.
PovRay - Create stunning 3D graphics
Art Of Illusion - A cool, free 3D modelling and rendering studio
Revolution 3D - A very complex 3D animation utility.