The Jabber::RPC::HTTPgate is an experimental package that
allows you to bridge traditional (HTTP-based) XML-RPC calls
and Jabber-RPC calls. 

With the Jabber::RPC::HTTPgate module you can set up a 
gateway between HTTP-based and Jabber-based XML-RPC, so 
a Jabber-RPC requester can make calls to an HTTP-based
responder, and vice versa. 

See the module documentation for more details. There are
lots of examples in the distribution.

http://www.pipetree.com/jabber/jrpc/httpgate/ is HTTPgate's 
home.