I am starting to make extensive use of XML Updategrams to post data to SQL Server. The first step is to install the MS XML for SQL Server download. You can get the SQL Server 2000 version at:
Once installed, you create a special XML virtual directory in IIS for direct HTTP posts. You also need to create an XSD or XDR schema of your SQL database. I would download the free SQL Server XML View Mapper from the MSDN site for that.
I then use Web Connects IPStuff library to do a direct HTTP post of the document. You can also user ADO to post the XML document, but I prefer the direct HTTP post to the virtual diectory. Once posted, SQL Server takes care of the rest and returns an XML string that you can parse and determine success or failure.