strtotime - 날짜 변환

$a = "7 Feb 2006 22:47:15 +0900";
$b = strtotime($a);
$c = date("Y-m-d H:i:s", $b);
echo $a."

";
echo $b."

";
echo $c."

";

-------

7 Feb 2006 22:47:15 +0900
1139320035
2006-02-07 22:47:15