After about 7 years, Microsoft have decided to re-activate WebMatrix aka “The Matrix” :-)
WebMatrix is everything you need to build Web sites using Windows. It includes IIS Developer Express (a development Web server), ASP.NET and SQL Server Compact (an embedded database). It streamlines Web site development and makes it easy to start Web sites from popular open-source apps. The skills and code you develop with WebMatrix transition seamlessly to Visual Studio and SQL Server.
You can download the beta here: http://www.microsoft.com/web/webmatrix/
The WebMatrix is a smaller / lighter product that the Express product series, which of course still are available for download. If you’re ‘lazy’ you can use the Microsoft Web Platform Installer 2.0 for easy setup / install.