static string login(string url, string username, string password)
        {
            HttpWebRequest req  = (HttpWebRequest)WebRequest.Create(url);
            string cookie       = "";
            string values       = "vb_login_username="+username+"&vb_login_password="+password
                                + "securitytoken=guest&"
                                + "cookieuser=checked&"
                                + "do=login";
            req.Method          = "POST";
            req.ContentType     = "application/x-www-form-urlencoded";
            req.ContentLength   = values.Length;
            CookieContainer a   = new CookieContainer();
            req.CookieContainer = a;

            System.Net.ServicePointManager.Expect100Continue = false; // prevents 417 error

            using (StreamWriter writer = new StreamWriter(req.GetRequestStream(), System.Text.Encoding.ASCII)) {writer.Write(values);}

            HttpWebResponse c = (HttpWebResponse)req.GetResponse();
            foreach (Cookie cook in c.Cookies){cookie = cookie + cook.ToString() + ";";}

            return cookie;
        }


    string cookie = login("forum.codecall.net/login.php?do=login", "username", "password"); // include http and www (I don't have 10 forum posts)
     Console.Write(cookie);
     Console.Read();