why not use rar?
it has a higher compression rate for its own files, than zip files do, plus it can handle most other kinds of compression. definitely all the types that winzip can do. It can handle .lhz files no bother, while winxip requires a plugin, and it does tar.gz files like a dream. the only things that rar doesn't do is support for disk spanned multiple zip files (which winzip 6, 7 and 8 do) and Stuffit archives (which winzip does not support either).
MacRar is available, as is WinRAR, and there's a program called rar available for linux, from the same company that does the same job.
The linux version appears not to have quite the same recency that the other versions have so be careful with your compression options if you want to put rar files across platforms. solid archives and multimedia compression don't seem to be supported in less up to date versions (though they make little difference to the filesize.)
You should be able to find all three versions at download.com or on google. the linux version and the mac version appear to be totally free, and the windows version costs $12 after a 40 day evaluation period is up. that said, i have had mine running more than 40 days in windows and no nag screen has come up, so maybe it's true goodwill style shareware, maybe i'll pay for it after all!
Anyway, that's my suggestion, though if you want to span disks and open .sit and .sea files, you will need winzip and stuffit expander as well (in win* that is)