I’ve been playing around with IIS recently. The Windows/IIS community is not nearly as well served by Open Source as the competition, which is unfortunate given that IIS is a really popular platform for intranets and other enterprise applications. It’s not really fair to ask your IT department to support Apache + MySQL as well as existing IIS + Microsoft SQL Server instances, especially if PHP can be installed, fairly easily, on IIS.
In hopes of one day running WordPress and MediaWiki well on IIS, I’ve been collecting links. First off, the simple recommendation is to just get the Microsoft Web Platform, which hopes to automate almost 100% of the process of PHP on IIS, including installing the FastCGI libraries that you’d probably want.
In case you’re trying to learn more about what’s actually going on, Bill S wrote up an extensive how-to for installing PHP on IIS. From the folks behind PHP, the documentation on php.net is pretty detailed, especially if you’re working with an older set of servers (like Windows XP + IIS 5). A detailed IIS 6 walkthrough can be found on the IIS Admin Blog.
Since this implementation uses CGI, and is still not as fast as the Apache+PHP stack, Ruslan has described how to make PHP faster on IIS using WinCache. Performance seems to be a big concern, in general.
Hopefully that helps someone!