Filling a form from XML (and let's say that it's XML generated by
server-side classic ASP script, so that it has something to do with this
newsgroup) is actually very easy.
The newer (5.0 and later) versions of Acrobat can read an XFDF file to load
the correct PDF form and populate its fields. The XFDF file is simply an
XML document which specifies fields values and the location of the PDF form
that goes with it.
Version 6.0 has a newer specification, Adobe XML Forms 2.0, which has
additional forms template options.
You can find out more about both schemas and specs at
http://partners.adobe.com/asn/tech/pdf/xmlformspec.jsp.
But in the end, the process can be as easy as generating a well-formed XML
document with nodes matching the fields in your PDF form.
--Boris