This is very useful if you need to make .zip files that are fully compatible with MSDOS, which the gzip included in OS X is definitely not. However the doc is slim to the point of transparency. For the record, in a terminal window, type "zip -h" for the help. To create an archive based on the directory ./foo, use "zip -rv9 foo". When you are going to send to a Wintel user, remember to cd into foo first and delete .DS_Store, a Finder file that frightens windows users.