FtpWebRequest request = (FtpWebRequest)FtpWebRequest.Create(@"ftp://ftp.somesite.com/somefile.txt");
            request.Credentials = new NetworkCredential(@"ftp_user", @"ftp_password");
            request.Method = WebRequestMethods.Ftp.DownloadFile;

            using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
            {
                using (StreamReader in_stream = new StreamReader(response.GetResponseStream()))
                {
                    using (StreamWriter out_stream = new StreamWriter(@"C:\localfile.txt", false))
                    {
                        char[] buffer = new char[1024];
                        while (!in_stream.EndOfStream)
                        {
                            int bytes_read = in_stream.Read(buffer, 0, buffer.Length);
                            out_stream.Write(buffer, 0, bytes_read);
                        }
                    }
                }
            }