$ more ~/bin/wdate
#!/bin/sh

if [ 0 != $# ]; then
        for t in $@; do
                S_ZONES="$S_ZONES -e $t"
        done
        ZONES=`find /usr/share/zoneinfo/ -type f | grep -v -e right -e zone.tab|
 sed -e 's#/usr/share/zoneinfo/##' -e 's#posix/##' |sort -u | grep -ix $S_ZONES`
else
        ZONES="America/Los_Angeles America/New_York UTC Europe/London Europe/Rom
e Hongkong Australia/Adelaide Australia/Melbourne NZ"
fi

for t in $ZONES; do
        d=`TZ=$t date`
        echo "$d ($t)"
done

----------
$ wdate
Sat Aug 25 09:04:54 PDT 2012 (America/Los_Angeles)
Sat Aug 25 12:04:54 EDT 2012 (America/New_York)
Sat Aug 25 16:04:54 UTC 2012 (UTC)
Sat Aug 25 17:04:54 BST 2012 (Europe/London)
Sat Aug 25 18:04:54 CEST 2012 (Europe/Rome)
Sun Aug 26 00:04:54 HKT 2012 (Hongkong)
Sun Aug 26 01:34:54 CST 2012 (Australia/Adelaide)
Sun Aug 26 02:04:54 EST 2012 (Australia/Melbourne)
Sun Aug 26 04:04:54 NZST 2012 (NZ)