#!/usr/bin/env python
# -*- coding: utf-8 -*-

import urllib
import urllib2
import re

USERNAME = 'username'
PASSWORD = 'password'

url = 'login_url'
data = urllib.urlencode({
    'vb_login_username': USERNAME,
    'vb_login_password': PASSWORD,
    'cookieuser': '1',
    's': '',
    'do': 'login',
    'forceredirect': '0',
    'vb_login_md5password': '',
})
headers = {
    'User-Agent': 'Mozilla/5.0 (Windows; U; Windows NT 5.1; ru; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5',
    'Referer': 'index_page_url',
}

req = urllib2.Request(url, data, headers)
page = urllib2.urlopen(req).read()
print page