use DateTime;

my $time = DateTime->now( time_zone => 'America/New_York' );
$time->set_time_zone( 'Australia/South' );
print "$time\n";

##</code><code>##

my $time = DateTime->new(
    year   => 2007,
    month  => 12,
    day    => 28,
    hour   => 18,
    minute => 30,
    second => 0,
    time_zone => 'America/New_York',
);

##</code><code>##

[jason@critter ~ 0]$ date
Fri Dec 28 13:24:04 EST 2007
# oops, there are two ESTs, one at -0500 and one at +1000/+1100, which one is it?
[jason@critter ~ 0]$ ls -l /etc/localtime
lrwxr-xr-x  1 root  wheel  30 Dec  5 12:06 /etc/localtime@ -> /usr/share/zoneinfo/US/Eastern