Chapter 1 of the Moodle 2.0 in Microsoft Technologies book discusses why you might want to consider using Microsoft technologies instead of Linux, Apache and MySQL.
Further into this chapter you are guided through the implementation of installing Moodle 2.0 on Windows Server 2008 R2 using PHP for Windows, IIS and SQL Server Express Edition.
Using SQL Server Express Edition keeps the cost on Moodle on a Microsoft environment to its lowest allowing you to implement the learning management tool for the cost of a Windows Server license. SQL Server Express is free and can be downloaded from the Microsoft site.
If you are interested in this chapter it can be purchased with the rest of the ebook in PDF, epub and mobil version for the BFC Networks shop.