Edit timestamp

<?php
    $this->tr_timestamp = "30/12/2011";
        if(strpos($this->tr_timestamp, "/") > 0) {
            list($day, $month, $year ) = explode("/", $this->tr_timestamp);
            $this->tr_timestamp = date('Y-m-d H:i:s', strtotime("$year-$month-$day"));
        }
?>