Alex Pearce posted to his blog (http://learninggateway.net/blogs/ajp/) a white paper that covers the installation process of Moodle on a Windows Server. He says,

Like me you might find implementing Moodle on a LAMP (Linux, Apache, MySQL and PHP) a little tricky and I personally want it on Windows Server, SQL Server and IIS.

A Windows System can scale differently to anything like MySQL and you can manage it in a high availability environment with Microsoft SQL Clustering and Mirroring.

Here is a whitepaper that I have put together on how to installing Moodle 1.9 on Windows Server 2008 x86, PHP5, SQL Server 2008 and IIS.

Get the white paper here: http://learninggateway.net/blogs/ajp/archive/2010/03/29/installing-moodle-on-windows-server-sql-iis.aspx.  Special thanks to Julian Ridden who tagged this in his Delicious account.

You also might find this Moodle.org resource handy: http://docs.moodle.org/en/Installing_Moodle