available timezones

Is there any way to retrieve an array of the available timezones on a Unix system for use with putenv("TZ=...")? Usually they're stored in /usr/share/zoneinfo/ on my Mac, but I don't like my chances of: - them being in the same place on every server - them being readable via a PHP script If there isn't such a function, a second option would be to check that whatever timezone I *plan* to use is available within the system. <? putenv("TZ=Australia/Melbourne") ?> may have no affect on my scripts if the TZ is not recognised by the server. --- Justin French http://indent.com.au