Getting a copy of WinZIP
You can download the latest version.
If you download the this version, you either have to pay for it, or
use an evaluation version.
For the evaluation version, use the button marked "Get WinZip Free"
The University of Nebraska maintains a nice WinZIP tutorial.
The makers of WinZIP maintain a WinZIP FAQ.
Instead of using WinZIP, you can also use PKZIP. You seem to be able
to download PKZIP for free.
For Mac Users
ZIP comes along with the Mac operating system. If you open a terminal
window and type:
you will get a list of options. You should be able to figure out from
this how to zip up your work.