PHPFreaks.com has posted this new information about running PHP on a Windows 2008 Server instance and how you can give it a try for thirty days.
Microsoft has been recently engaging in a number of open source projects. They have been working on enhancing performance, security and stability of PHP applications on Windows Server platforms. [...] In cooperation with Microsoft, [we] invite you to trial a Windows based web stack consisting of IIS 7, PHP 5 and SQL Server. Via the PHP on WS 2008 website you will be able to request a 30-day trial with a Microsoft hosting partner
By signing up, you can request a trial of the IIS 7 software. They also provide a Q&A discussion board for those participating in the program that might need any help.