Yemuzip was recommended at CMSExpo for zipping Joomla templates, modules, extensions, etc.  because it doesn’t include some Mac junk that the Finder’s Compress command does.  I haven’t had trouble with normal Mac zip files as long as I didn’t have any files with **s or other special characters in the file or folder names.

I downloaded this and tried it.  It’s very easy to use and offers PC or Mac compatibility.

http://yellowmug.com/yemuzip/