I'm going to blatantly steal Bill Staples words since they were so good :)
"I’m excited to announce the availability of the Release Candidate version of the Microsoft Web Platform Installer (Web PI).
Web PI is a free tool that makes it simple to download and install the latest components of the Microsoft Web Platform, including IIS, ASP.NET, Visual Web Developer Express and SQL Server, along with a lot of cool IIS extensions like URL rewrite and ASP.NET MVC.
Web PI offers a simple experience for downloading and installing the entire stack through a single installer to help you obtain the software you need to build and run a complete Web solution on the Microsoft Web platform, whether you are using Windows XP, Windows Server 2003, Windows Vista, or Windows Server 2008.
Run Web PI to get started and then run it again anytime to check for new extensions to the platform. Every time Web PI is run it checks online to ensure the most current versions and new additions to the Microsoft Web Platform are downloaded. Give Web PI a try today!"