If you installed IIS on Windows Vista after you installed .NET 3.0, like I did, you’ll notice that any references to the .svc file will fail, typically with a 404 not found. It’s easy to see that the .svc mappings aren’t installed, but without consulting some documentation it’s not abundantly clear how to install them. If you’re running Vista, you enable the activation service by turning on a windows feature: Windows Communication Foundation HTTP Activation. You can access the “Turn Windows features on or off” option from your Control Panel.
Hope this saves someone else the time I wasted. 
April 14, 2008 at 13:16
This was perfect to get Vista setup for WCF debug without having to dig through MSDN. Thank you.