This evening a download was added to the ASP.NET Security Vulnerability information page. It sounds like there is more to come but this is a start.
Note This page was updated October 7, 2004, to include information about a newly released mitigation option, an HTTP module installer. This module protects all ASP.NET applications on a Web server against canonicalization problems that are currently known to Microsoft as of the publication date. We will continue to update this page as additional guidance and resources become available.