I tried niceandsimple contact from this website, worked wonderful. But after getting so many spam mails, i decided to add recaptcha although I followed all instructions still its not working. Tutorial Link here is my website and here is code

  <form method="post" action="contactengine.php">
        <label for="Name">Name:</label>
        <input type="text" name="Name" id="Name" />

        <label for="Email">Email:</label>
        <input type="text" name="Email" id="Email" />

        <label for="Message">Message:</label><br />
        <textarea name="Message" rows="20" cols="20" id="Message"></textarea>

          >       
       <div id="captcha-area">

        <?php

        require_once('recaptchalib.php');
        $publickey = "6Ld9ltwSAAAAAKnB4ANn4baVx@@@@@@@@";
        $privatekey = "6Ld9ltwSAAAAAGa8lKr7QzaDD52M********";

        # the response from reCAPTCHA
        $resp = null;
        # the error code from reCAPTCHA, if any
        $error = null;

        # are we submitting the page?
        if ($_POST["submit"]) {
          $resp = recaptcha_check_answer ($privatekey,
                          $_SERVER["REMOTE_ADDR"],
                          $_POST["recaptcha_challenge_field"],
                          $_POST["recaptcha_response_field"]);

          if ($resp->is_valid) {
          echo "You got it!";
          # in a real application, you should send an email, create an account, etc
          } else {
          # set the error code so that we can display it. You could also use
          # die ("reCAPTCHA failed"), but using the error message is
          # more user friendly
          $error = $resp->error;
          }
        }
        echo recaptcha_get_html($publickey, $error);
        ?>

        </div>

        <input type="submit" name="submit" value="Submit" class="submit-button" />
      </form>