$date = 'Sat, 23 Dec 2006 10:05:50 GMT+8';
$date = array_shift(explode("GMT", $date));
echo date('Y-m-d H:i:s', strtotime($date));
$date = array_shift(explode("GMT", $date));
echo date('Y-m-d H:i:s', strtotime($date));
list($d, $h) = explode("GMT", $date);
echo date('Y-m-d H:i:s', strtotime("$h hours", strtotime($d)));