free zip file??? as in that can make files into zip files???
if you're on windows you should automatically have winzip installed which is the standard one. if not google "winzip" and download it, another similar thing is "winrar" which isn't standard on windows computers but can zip files and also rar files which can break them down to smaller chunks for easier transportation and also add a password to rar'd files too.
so if you just wanna zip files "winzip" is your thing or if you want to add a few other bits "winrar" would be for you.
both tried, tested, virus free.