Requests and Beautiful Soup example, following the form of http://bpaste.net/show/kMetvCdrfnzh5RgiUKU4/

example.py

from BeautifulSoup import BeautifulSoup
import requests
import urlparse

URL = 'example.com'
s = requests.Session()

def fetch(url, data=None):
    if data is None:
        return s.get(url).content
    else:
        return s.post(url, data=data).content

soup = BeautifulSoup(fetch(URL))
form = soup.find('form')
fields = form.findAll('input')

formdata = dict( (field.get('name'), field.get('value')) for field in fields)

formdata['username'] = u'username'
formdata['password'] = u'password'

print formdata
posturl = urlparse.urljoin(URL, form['action'])
print posturl

r = s.post(posturl, data=formdata)
print r.text

print s.get(URL).text