#coding=utf8
import urllib
import urllib2
import re

email = ''
password = ''

host = 'http://vk.com'
postdata = urllib.urlencode({'act': 'login',
                             'q': '1',
                             'al_frame': '1',
                             'from_host': 'vk.com',
                             'email': email,
                             'pass': password
})
headers = {'Host': 'login.vk.com',
           'User-Agent': 'Mozilla/5.0 (X11; Linux i686; rv:6.0.2) Gecko/20100101 Firefox/6.0.2',
           'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
           'Accept-Language': 'ru-ru,ru;q=0.8,en-us;q=0.5,en;q=0.3',
           'Accept-Encoding': 'gzip, deflate',
           'Accept-Charset': 'windows-1251,utf-8;q=0.7,*;q=0.7',
           'Connection': 'close',
           'Referer': 'http://vk.com/al_index.php?act=auth_frame',
           'Cookie': 'remixlang=3; remixchk=5'
}
req = urllib2.Request(host, postdata, headers)
res = urllib2.urlopen(req).read()
print res

$  python ut1.py
Traceback (most recent call last):
  File "ut1.py", line 26, in <module>
    res = urllib2.urlopen(req)
  File "/usr/lib/python2.6/urllib2.py", line 126, in urlopen
    return _opener.open(url, data, timeout)
  File "/usr/lib/python2.6/urllib2.py", line 397, in open
    response = meth(req, response)
  File "/usr/lib/python2.6/urllib2.py", line 510, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.6/urllib2.py", line 429, in error
    result = self._call_chain(*args)
  File "/usr/lib/python2.6/urllib2.py", line 369, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.6/urllib2.py", line 616, in http_error_302
    return self.parent.open(new, timeout=req.timeout)
  File "/usr/lib/python2.6/urllib2.py", line 397, in open
    response = meth(req, response)
  File "/usr/lib/python2.6/urllib2.py", line 510, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.6/urllib2.py", line 435, in error
    return self._call_chain(*args)
  File "/usr/lib/python2.6/urllib2.py", line 369, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.6/urllib2.py", line 518, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
urllib2.HTTPError: HTTP Error 403: Forbidden

host = 'http://vk.com'
'Host': 'login.vk.com'