t = Time.now
# => 2012-11-05 11:12:25 -0500
t.to_i
# => 1352131945
tu = t.utc
# => 2012-11-05 16:12:25 UTC
tu.to_i
# => 1352131945
php > date_default_timezone_set("UTC");
php > $t = new DateTime("@1352131945");
php > echo date_format($t, "Y-m-d H:i:s");
2012-11-05 16:12:25
php > echo date_format($t, "Y-m-d H:i:s e");
2012-11-05 16:12:25 +00:00