Is there a native implementation of JSON in Windows that I can call from C? If not, what about .NET or C#? Or what if any library or implementation do people use when they w
There is a long list of such things on the JSON homepage. Take your pick.
Yes, there is a built-in Windows JSON parser: http://msdn.microsoft.com/en-us/library/system.web.script.serialization.javascriptserializer.aspx
It can be called from a native language using the .NET interop facilities (COM Callable Wrapper), which may be more work for you than a truly native library, as first answer suggests.