A WSDL file contains a Schema that defines the XML Types transferred from
client to server.  However, from what I can tell, this schema is never
validated by the default MS implementation of the Web Service class.

I know that I could, within the server's implementation, validate the input
by taking the concrete class and running it through a reserialization process
that would validate the XML against a given schema.  However, I was wondering
if there was a more intrinsic way of doing this (e.g. an HTTP filter of some
sort).
If not, is there something else out there that can create Client/Server
objects for Web Services that will validate the information?

I tend to create rather strict XSD definitions (e.g. Enumerations, etc) and
as it is, none of the imput documents, defined by an XSD Schema, are
validated against that schema.