import requests
from BeautifulSoup import BeautifulSoup as bs

sess = requests.Session()
USER = 'user'
PASS = 'pass'

print "logueandome..."

login = sess.post("http://registro.educ.ar/cuentas/ServicioLogin/index", data=dict(login_user_name=USER,
                               login_user_password=PASS,
                               servicio='encuentro',
                               continuar="http%3A//www.encuentro.gob.ar/sitios/encuentro/Programas/loginCallBack%3Fmethod%3Dlogin"
                              ))
print "sacando la cookie de",
print login.url
sess.get(login.url) # aca me da la session id
print "sacando el link..."
url = "http://www.encuentro.gob.ar/sitios/encuentro/Programas/ver?rec_id=120761"
html = sess.get(url).content
bs_html = bs(html)
link = dict(bs_html.find(attrs={'class': 'descargas'}).find('a').attrs)['href']
print link