When using Active Server Pages to make XMLHTTP requests, you can use both GET and POST. But for POST to work, you need to remember a content-type as well.
DataToSend = "id=1"
dim xmlhttp
set xmlhttp = server.Createobject("MSXML2.ServerXMLHTTP")
xmlhttp.Open "POST","http://localhost/Receiver.asp",false
xmlhttp.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
xmlhttp.send DataToSend
Response.ContentType = "text/xml"
Response.Write xmlhttp.responsexml.xml
Set xmlhttp = nothing