With a little help from Mike Volodarksy's tutorial I'm up and running with RubyOnRails using a native FastCGI implementation. This is a big deal because it'll mean that Microsoft will provide a supported way of running Rails applications. In addition, PHP applications will be able to run with greater performance and reliability thanks to the work that Zend and other PHP devs have put into improving their Windows story.
This is a good job since I'm doing more work with these open source technologies at the moment since Microsoft have done little to improve the ASP.NET platform. For .NET developers, MonoRail is the only usable framework for development. Additions such as ASP.NET AJAX do little to make the platform better for the applications I am working on. The problem with AJAX is that it's not an end in itself. You need to have a reason to use it and a design to match, or you end up on the road to poor performance and usability.
Unlike the Apache HTTP server, Microsoft's IIS currently doesn't have a built-in extension offering support for URL rewriting and 'proxying' of server requests. This means that you have to hack up some code to manually process URLs with ASP.NET or implement a nasty 404 handler in classic ASP.
Recently, I needed to centralise a number of services under a single domain name on one of my machines. Normally, an Apache user would use mod_rewrite to proxy requests through to another machine. I wanted to do this on IIS so I evaluated a number of ISAPI filters which purport to offer similar functionality. The candidates were ISAPI Rewrite, IISRewrite and OpUrl. After some spelunking in my Win2K3 virtual machine I decided to purchase an ISAPI Rewrite license. It fairly cheap and questions posted to the support forum are answered promptly.
I posted some setup instructions for proxying requests to a Kerio webmail server on their forums.