Cool hack in Unix: if you know the zonefile abbreviation for a timezone, you can use it to get the date there:
$ TZ=PST8PDT date
Tue Aug 30 05:07:39 PDT 2005
This also works:
$ TZ=America/Los_Angeles date
Tue Aug 30 05:08:17 PDT 2005
Timezone files are in /usr/share/zoneinfo on OpenBSD and Linux.