All you need to do is add an HTTP header, and send the data the same way you'd send it on the QueryString.

Here's a JScript example for the client side, that submits form data to another page:

  var objHTTP, strResult;
  objHTTP = new ActiveXObject('Microsoft.XMLHTTP');
  objHTTP.open('POST',"OtherPage.asp",false);
  objHTTP.setRequestHeader('Content-Type',
'application/x-www-form-urlencoded');

  objHTTP.send("id=1&user="+txtUser.value+"&password="+txtPassword.value);

  strResult=objHTTP.responseText;