<?php
// � necess�rio usar o formato MM-DD-AAAA nessa fun��o
function date_diff($from, $to) {
  list($from_month, $from_day, $from_year) = explode(\"-\", $from);
  list($to_month, $to_day, $to_year) = explode(\"-\", $to);
        
  $from_date = mktime(0,0,0,$from_month,$from_day,$from_year);
  $to_date = mktime(0,0,0,$to_month,$to_day,$to_year);
        
  $days = ($to_date - $from_date)/86400;
        
  return $days;
}
?>
A diferen�a de dias entre duas datas seria: <br>
<?php $days = date_diff(\"10-1-2000\",\"10-9-2000\"); ?>