import urllib.request
from urllib.parse import urlencode
headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:33.0) Gecko/20100101 Firefox/33.0',
                 'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'}
data = urlencode({'email' : '*******@*****.ru', 'pass' : '*********'}).encode()
vk = urllib.request.Request('http://vk.com/login.php?u=2&to=YWfaW0D1jMTk2', data, headers)
respone = opener.open(vk)
# Для отладки
output = open('vk_output.html', 'wb')
output.write(respone.read())

import urllib.request
import urllib.parse
import http.cookiejar
EMAIL = "xxx@xxx.ru"
PASS =  "xxxxxxxxxx"
cookie = http.cookiejar.CookieJar()
opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cookie))
opener.addhandler = [('User-Agent', 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:35.0) Gecko/20100101 Firefox/35.0')]
urllib.request.install_opener(opener)
opener.open('https://login.vk.com/?act=login',
            urllib.parse.urlencode({'email': EMAIL, 'pass': PASS}).encode())