LaTeX is a typesetting program for mathematical documents. It is extremely powerful, and not too hard to learn to use. The easiest way is to modify someone else's file, so I will provide some below. There are also many resources online to help. MiKTeX and WinEdt are available in the Collins 407 computer lab, so you do not need a personal copy. However, if you want one, you will need both MiKTeX and a LaTeX editor.
If you have a Mac, you can get a complete LaTeX setup (for free) from U of O. Just follow the directions. Get MiKTeX (Select the Phoenix download site.)
Get a personal copy of WinEdt for $30, or download a free LaTeX editor. I recommend WinEdt; it is very powerful and easy to use, and it's the one I know best.
Here are some LaTeX files to get you started.
Links