Un ejemplo de  código para enviar  request   desde Netduino a url usando post:

private static string pMessage;
public static ManualResetEvent allDone = new ManualResetEvent(false);

private void Form1_Load(object sender, EventArgs e) {
try {

//string serviceURL = «http://localhost:52976/SL2Astoria_Web/WebDataService.svc/Products/»;
string serviceURL = «http://localhost:52895/Service1.asmx/Service1»;

pMessage = «{» + Environment.NewLine;
pMessage += «ProductName=\»zone\»» + Environment.NewLine;
pMessage += «}» + Environment.NewLine;

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(serviceURL);
request.ContentType = «application/json»;
request.UserAgent = «Fiddler»;
//request.ContentType = «application/x-www-form-urlencoded»;
request.Method = «POST»;
request.BeginGetRequestStream(new AsyncCallback(ReadCallback), request);

// Keep the main thread from continuing while the asynchronous
// operation completes. A real world application
// could do something useful such as updating its user interface.
allDone.WaitOne();

}
catch (Exception ex) {
Console.Write(ex.Message);
}

}

private static void ReadCallback(IAsyncResult asynchronousResult) {
HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
// End the operation.
Stream postStream = request.EndGetRequestStream(asynchronousResult);

string postData = pMessage;

// Convert the string into a byte array.
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Write to the request stream.
postStream.Write(byteArray, 0, postData.Length);
postStream.Close();
allDone.Set();
}

fuente original :http://social.msdn.microsoft.com/Forums/en-US/adodotnetdataservices/thread/c7854122-b61c-4f2c-aa44-831bf1d27af1/