Or you could use http://www.servicestack.net to host your same single web service on JSON, XML, CSV, JSV, HTML, SOAP 1.1, 1.2 endpoints out of the box, with no config or code-gen for free on .NET or Linux/Mono in ASP.NET or in a Console/WinService with HttpListener with C# or easily with F#: http://www.servicestack.net/mythz_blog/?p=785
ServiceStack also includes the 2 fastest text serializers for .NET (JSON/JSV) - many factor of times faster than all of the JSON serializers in .NET:
http://www.servicestack.net/benchmarks/
Seconded. I love .NET, but I hate how MS's not-invented-here syndrome repeatedly (albeit unintendedly) kills great open source projects. (point in case: NDoc vs Sandcastle). Really hope this won't happen to Servicestack