I have found a solution. using POST from the first form to the second page but not inserting to db yet. Then on the second form when a user submits or "place order", It will insert the billing and shipping info. Right after inset, using "mysql_insert_id($connection)" to extract immediately the inserted id for insert to the second table.
if ((isset($POST["MM_insert"])) && ($POST["MM_insert"] == "form1")) {
$insertSQL = sprintf("INSERT INTO orders (payment, firstName, lastName, email, street, suite, city, province, country, postal, telephone, shipfirstName, shiplastName, shipemail, shipstreet, shipsuite, shipcity, shipprovince, shipcountry, shippostal, shiptelephone, userID, status) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)",
GetSQLValueString($POST['payment'], "text"),
GetSQLValueString($POST['firstName'], "text"),
GetSQLValueString($POST['lastName'], "text"),
GetSQLValueString($POST['email'], "text"),
GetSQLValueString($POST['street'], "text"),
GetSQLValueString($POST['suite'], "text"),
GetSQLValueString($POST['city'], "text"),
GetSQLValueString($POST['province'], "text"),
GetSQLValueString($POST['country'], "text"),
GetSQLValueString($POST['postal'], "text"),
GetSQLValueString($POST['telephone'], "text"),
GetSQLValueString($POST['shipfirstName'], "text"),
GetSQLValueString($POST['shiplastName'], "text"),
GetSQLValueString($POST['shipemail'], "text"),
GetSQLValueString($POST['shipstreet'], "text"),
GetSQLValueString($POST['shipsuite'], "text"),
GetSQLValueString($POST['shipcity'], "text"),
GetSQLValueString($POST['shipprovince'], "text"),
GetSQLValueString($POST['shipcountry'], "text"),
GetSQLValueString($POST['shippostal'], "text"),
GetSQLValueString($POST['shiptelephone'], "text"),
GetSQLValueString($POST['userID'], "int"),
GetSQLValueString($_POST['status'], "text"));
mysql_select_db($database, $dbconnect);
$Result1 = mysql_query($insertSQL, $dbconnect) or die(mysql_error());
$ordersID = mysql_insert_id($dbconnect);
echo "<script>";
echo "document.form2.orderID.value ='".$ordersID."';";
echo "form2.submit();";
echo "</script>";