Sample-Code:Translator

  <h2>My Spanish Translator</h2>

       <p>

            Enter your text in English:&nbsp; </p>

       <p>

           <asp:TextBox ID="TextBox1" runat="server"  

             Width="198px"></asp:TextBox>

       </p>

     <p>

           <asp:Button ID="Button1" runat="server" onclick="Button1_Click" 

                Text="Translate" />

       </p>

       <p>

            Here is your translation:</p>

      <p>

           <asp:Literal ID="lbl1" runat="server"></asp:Literal>

      </p>

button code:

 string clientID = "<Your ClientID>";

            string clientSecret = "<Your Client Secret>";



            String strTranslatorAccessURI = "https://datamarket.accesscontrol.windows.net/v2/OAuth2-13";

            String strRequestDetails = string.Format("grant_type=client_credentials&client_id={0}&client_secret={1}&scope=http://api.microsofttranslator.com", HttpUtility.UrlEncode(clientID), HttpUtility.UrlEncode(clientSecret));



            System.Net.WebRequest webRequest = System.Net.WebRequest.Create(strTranslatorAccessURI);

            webRequest.ContentType = "application/x-www-form-urlencoded";

            webRequest.Method = "POST";



            byte[] bytes = System.Text.Encoding.ASCII.GetBytes(strRequestDetails);

            webRequest.ContentLength = bytes.Length;

            using (System.IO.Stream outputStream = webRequest.GetRequestStream())

            {

                outputStream.Write(bytes, 0, bytes.Length);

            }

            System.Net.WebResponse webResponse = webRequest.GetResponse();



            System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(typeof(AdmAccessToken));

            //Get deserialized object from JSON stream 

            AdmAccessToken token = (AdmAccessToken)serializer.ReadObject(webResponse.GetResponseStream());



            string headerValue = "Bearer " + token.access_token;



            string txtToTranslate = TextBox1.Text;

            string uri = "http://api.microsofttranslator.com/v2/Http.svc/Translate?text=" + System.Web.HttpUtility.UrlEncode(txtToTranslate) + "&from=en&to=es";

            System.Net.WebRequest translationWebRequest = System.Net.WebRequest.Create(uri);

            translationWebRequest.Headers.Add("Authorization", headerValue);

            System.Net.WebResponse response = null;

            response = translationWebRequest.GetResponse();

            System.IO.Stream stream = response.GetResponseStream();

            System.Text.Encoding encode = System.Text.Encoding.GetEncoding("utf-8");

            System.IO.StreamReader translatedStream = new System.IO.StreamReader(stream, encode);

            System.Xml.XmlDocument xTranslation = new System.Xml.XmlDocument();

            xTranslation.LoadXml(translatedStream.ReadToEnd());

            lbl1.Text = "Your Translation is: " + xTranslation.InnerText;

AdmAccessToken Class:

  public class AdmAccessToken

       {

    

           public string access_token { get; set; }

 

          public string token_type { get; set; }

    

           public string expires_in { get; set; }

     

            public string scope { get; set; }

      }

 

Resource from: http://blogs.msdn.com/b/translation/p/gettingstarted1.aspx