codice:
function compleanno($temp)
{
  if($temp == '0000-00-00')
  return FALSE; 

  $temp = explode("-",$temp);
  $oggi = explode("-",date("Y-m-d"));

  if ($oggi[1] > $temp[1])
  return $oggi[0] - $temp[0];
              elseif ($oggi[1] >= $temp[1] && $oggi[2] >= $temp[2])
              return $oggi[0] - $temp[0];
                    else
                    return $oggi[0] - $temp[0] - 1;
}
echo compleanno("2000-08-29");