$ENV{TZ}="Europe/Paris";
my $t=localtime();
print "main (Europe/Paris): ",$t,"\n";

$ENV{TZ}="Europe/Moscow";
$t=localtime();
print "main (Europe/Moscow): ",$t,"\n";

##</code><code>##

main (Europe/Paris): Tue Nov 24 23:27:28 2009
main (Europe/Moscow): Wed Nov 25 01:27:28 2009