TimeZone List

I've been trying to sort out the answer to this question for a while
now, I've received different answers from different places.

I'm looking for a definitive non-volatile list of timezones for use in a
web application. I can't use the OS's time zone list, as changing OSes
may cause some listed timezones to disappear or change name, causing
havoc for any entries in the DB referring to those zones.

Is relying on zone.tab to be a non-volatile list of timezones
appropriate for this purpose? Or is there an ISO listing of the various
time zones? I would prefer to use a list that matched the PostgreSQL
DB's internal timezone strings so they could easily be referenced
without any further work in the app.

Thanks
- Naz.