I come across this sort of thing and always feel behind the times.
Google has this 3D modeling program called SketchUp that is apparently already on version 6. I haven't tried it yet, but it looks like it's pretty easy to use. It's no
3DStudio but it'll do in a pinch. Plus you can then place your 3D model on
Google Earth so you can see what it will look like out in the world. Cool!