Marshal an object in an http request?

[boohoo@yutzy.com]

Let's say I want to use the msxml object to call a web page from
within my script, and on the querystring or "in the header" of that
request I want to include a dictionary object, such that the called
.asp page can then request the object to it's script and use the
dictionary object.

Has anyone seen anything that describes marshaling an object into an
http request header?