That's not a UNIX or MySQL timestamp though. That's just the numbers of a date concatenated together.
Try this:
<?
$months = array("JAN", "FEB", "MAR", "APR", "MAY", "JUN", "JUL", "AUG", "SEP", "OCT", "NOV", "DEC");
$article_date = '20031225020519';
preg_match('/(\d{4})(\d{2})(\d{2}).*/', $article_date, $matches);
printf('%d %s %d', $matches[3], $months[$matches[2]-1], $matches[1]);
?>
Diego