We will be using AutoDesk Inventor in this class. You can download it here. You have to register first. Otherwise the download link doesn't appear. I recommend Inventor 2013, since it is the latest.
Another good CAD program to use is Creo 2.0 (formally ProE). You can download it here if you like, but this will not be covered in class. However, you will quickly learn that if you know one CAD software package, learning another one is very easy.
Bought a Mac? Well, at least you look good in a coffee shop. However, neither of these programs runs on a MAC. In fact, no serious CAD program that works on a Mac. Install Parallels or bootcamp on your computer.