As a Web Platform evangelist at Microsoft, I've had many conversations with individuals about the how we could improve Microsoft's IIS Web Server. I've often touted the modular architecture implementation of IIS7, and how it allows both Microsoft and other parties to easily enhance, tweak, and improve the functionality of the web server to meet the specific requirements of the job at hand. To date, many IIS7 modules have been released, both by Microsoft as well as third parties. When examining what kinds of functionality the Microsoft IIS product team should be spending cycles developing modules for, one of the most commonly requested modules was one implementing functionality similar to Apache's Mod-Rewrite.
Last week, the IIS7 team announced a go-live version of an IIS7 module to give this functionality. It's called URL-Rewrite, and you can find more information about it at http://blogs.iis.net/ruslany/archive/2008/09/11/url-rewrite-module-go-live-release.aspx
At a high level, the Microsoft URL Rewrite Module for IIS 7.0 provides flexible rules-based rewrite engine that can be used to perform broad spectrum of URL manipulation tasks, including, but not limited to:
For a full list of features, usage scenarios, and download locations check out: http://learn.iis.net/page.aspx/460/using-url-rewrite-module/