I've built a simple .Net DLL that can be used on any ASP.Net site to handle dynamic redirects of requests coming into that website.  This will allow you to dynamically redirect an incomming url based on the url being sent in.  YOu can recombine the elements from the requested Url to build a new Url to be redirected to or transparently transferred to.

 

The component is called Geeqs.Net.Urlrewriter and you can configure it by adding RegEx rules to your web.config file.  As a component, it can be just dropped into any existing ASP.Net 1.1 site without having to modify your site.

 

See the deets here: http://blog.geeqs.net/archive/2006/04/18/Geeqs_Net_UrlRewriter.aspx