Transferring XML Documents

Hi Everyone, Merry Xmas! I've been working with XML now for almost a year, and I now have an application that I want to "web enable", but I'm not really sure where I need to start if I choose PHP as the server side scripting environment. I'll have Xerces/Xalan installed on my server. I want remote microsoft users to be able to send documents to my server using the new msxml2.serverxmlhttp() method and I want remote php users to be able to do the same thing, but I'm not sure how. How would a remote php user send an XML document to my server? (besides posting an HTML form of course) Can they fopen("http://www.myserver.com/mypage.php", "w" ) and then fwrite() to my page? I've looked into SOAP, but that seems like more than what I need. Regards, Gary H.