using System.Net;

         [OperationContract]
        public void DMSend(string username, string recipient, string tweet)
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://twitter.com/direct_messages/new.xml?user=" + recipient + "&text=" + tweet);
            req.Method = "POST";
            req.Credentials = new NetworkCredential(username, password);
            req.ContentLength = 0;
            req.ContentType = "application/x-www-form-urlencoded";
            WebResponse response = req.GetResponse();
        }