String url = "http://api.clickatell.com/http/sendmsg?";
    List<NameValuePair> params = new LinkedList<NameValuePair>();
    params.add(new BasicNameValuePair("user", "user"));
    params.add(new BasicNameValuePair("password", "password"));
    params.add(new BasicNameValuePair("api_id", "XXXXX"));
    params.add(new BasicNameValuePair("to", "1XXXXXXXXXX"));
    params.add(new BasicNameValuePair("text", "Demo Message"));
    params.add(new BasicNameValuePair("from", "my-two-way-number"));
    params.add(new BasicNameValuePair("mo", "1"));

    String paramString = URLEncodedUtils.format(params, "utf-8");
    url += paramString;
    HttpGet get = new HttpGet(url);

    HttpResponse response = client.execute(get);