LaTeX is a document markup language and document preparation system for the TeX typesetting program.
It’s what I and most math/stats/econometrics teachers use to create the lecture slides and tutorials. If you’re thinking about doing honours, or postgraduate study in these fields it’s probably not a bad idea to start playing with LaTeX as it is the default standard for typesetting theses, journal articles and the like.
To get started you need to download and install TeX on your computer.
It is a WYMIWYG (What You Mean Is What You Get) system for typesetting, as opposed to Word which is WYSIWYG (What You See Is What You Get). This means that it has a really steep learning curve and can be quite strange at first. The best way to learn is by adapting what others have already done. Here are some resources to get you started:
A more user-friendly way to get started is with LyX. It’s more of a Word-like front end to LaTeX. You still need a TeX distribution installed before you can use that software.
Best of all, all of it’s free!