One of the often heard requests for IIS has been about the need to have a more flexible, rules based URL rewriting system. The IIS team is making good on it's promise to release some out of band updates to the server using the modular pipeline. From all appearances, this is a really nice first release of a url rewrite system that comes complete with a UI. For example, you could redirect to a specific page based on the contents of URL, server variables or http headers. Examining the headers lets you make routing decisions based on the host header for example.

This is a pre-release version so  be sure to give the team some feed back over on iis.net

IIS.net : Learn IIS7: Using URL Rewrite Module: Installing and Configuring IIS 7.0