Microsoft recently posted a 5 page PDF (3 pages of content) titled…
PHP on Windows: Community Involvement Improves Performance (5 page PDF download)
The paper focuses on the background of two projects that enhanced the use of PHP on Windows Servers. The first effort described is the partnership between Microsoft and Zend that resulted in the development of the FastCGI Extension that essentially allowed PHP to be a first-class citizen when used on a Windows Server with IIS. The second effort described is the Microsoft SQL Server 2005 Driver for PHP developed internally by the SQL Server team.
Two other projects are briefly mentioned at the end of the paper. The first is the Phalanger project which is a PHP compiler for the .NET Framework (and Mono). The other is the PHP for Microsoft AJAX Library.