json support in visual studio 2010
I use System.Web.Script.Serialization.JavaScriptSerializer
However, since it does not work in Visual Studio 2010 without configuration, you'll have to figure out how to make it work yourself.
I've been using Json.Net. (http://james.newtonking.com/pages/json-net.aspx) to serialize.
[Update: http://json.codeplex.com/ for latest version]
[Update Sept 27 2017: https://github.com/JamesNK/Newtonsoft.Json latest version no longer works in visual studio 2010]
Here you can find a very well-written open-source solution for parsing JSON data:
http://techblog.procurios.nl/k/618/news/view/14605/14863/How-do-I-write-my-own-parser-for-JSON.html
It is not native, but I have used it recently and did the job...