The basis idea is to use the substr function and the mktime function to convert it into a timestamp. You can then use the date function to get whatever format you want.
Here is an example that converts a string in YYYYMMDD format. You should be able to modify it to suit your needs.
function format_date($date)
{
$timestamp = mktime(0,0,0,
substr($date,4,2),
substr($date,6,2),
substr($date,0,4));
$date_str = date('D M d',$timestamp);
return $date_str;
}