XAP has to be a MIME Type

I love the VS embedded Web server, but it too often makes you thinking that things are easier than in the real and bitter world. So a trivial Silverlight 2.0 sample page that works from within the auto-generated ASP.NET Web site stops working as you create an IIS application for it. The symptom? No Silverlight content shows up and any network monitor tool you use reports that no XAP resource was found. But the resource is there. It's a simple matter of configuring IIS, though.

I was going to write a post myself. But then I found out that someone already did it. And it's a great write-up.