Auto-connect to OpenVPN. See http://selfamusementpark.com/blog/2009/03/07/automatic-wireless-goodness/

02startvpn

#!/usr/bin/python
#
# startvpn: Automatically connect to a VPN when associating with a 
# wireless network
#
# Once you've successfully set up an OpenVPN connection in NetworkManager, 
# configure the settings below, then install this script as 
# /etc/NetworkManager/dispatcher.d/02startvpn (it seems to be happiest
# when chowned root:root)
#
#--
# Copyright (c) 2008-2009 Bryan Stearns
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#--
#
# Configuration:
#
# The name of your VPN, as you've set it in Network Manager
VPN_NAME = "HomeVPN"

# Networks where no VPN is needed (eg, home)
PRIVATE_ESSIDS = ["linksys"]

# Automatically accept the Personal Telco Project EULA page
# for networks with these names:
PTP_ESSIDS = ["www.personaltelco.net"]
# (If I encounter other oft-hit pages like this, I'll generalize
#  this mechanism...)

# --- that's all ---

import sys, os, re, syslog, dbus, httplib, urllib, urlparse, commands
from dbus.mainloop.glib import DBusGMainLoop

NM_SERVICE="org.freedesktop.NetworkManager"
NM_PATH="/org/freedesktop/NetworkManager"

NM_VPN_SERVICE ="org.freedesktop.NetworkManager.VPNConnections"
NM_VPN_PATH    ="/org/freedesktop/NetworkManager/VPNConnections"

pid = os.getpid()
def log(msg):
  msg = "%s: %s" % (pid, repr(msg))
  print msg
  syslog.syslog(syslog.LOG_INFO, msg)

def doit():
  if len(sys.argv) == 3:
    interface, status = sys.argv[1:3]
  else:
    log("Usage: /etc/NetworkManager/dispatcher.d/02startvpn <interface> <status>")
    sys.exit(0)
  if status != "up":
    # log("New status for '%s' is '%s'; ignoring" % (interface, status))
    sys.exit(0)

  iwconfig = commands.getoutput("iwconfig %s" % interface)
  essid = re.search(r"""ESSID:"(.*?)" """, iwconfig).group(1) 
  log("New wireless network association: '%s'" % essid)

  if essid in PRIVATE_ESSIDS:
    log("Not starting VPN: we're home")
    sys.exit(0)

  if essid in PTP_ESSIDS:
    log("Checking for PTP EULAwall")
    filename, headers = urllib.urlretrieve("http://example.com/index.html")
    f = open(filename)
    data = f.read()
    f.close()
    # log("Got from GET: '%s'" % data)
        
    if data.find("<TITLE>Example Web Page</TITLE>") != -1:
      log("PTP EULAwall already breached")
    else:
      log("Looking for the PTP EULA form")
      action_match = re.search("form .* action=\"http://(.*)/\"", data)
      if action_match is None:
        log("Hmm, doesn't look like the PTP form")
        sys.exit(0)
      action = action_match.groups(1)[0]
      params = urllib.urlencode({'redirect': 'http://example.com', 
                                 'mode_login': 'I Agree'})
      headers = {"Content-type": "application/x-www-form-urlencoded",
                 "Accept": "text/plain"}
      conn = httplib.HTTPConnection(action)
      conn.request("POST", "/", params, headers)
      response = conn.getresponse()
      data = response.read()
      conn.close()
      log("Got %s / %s from POST" % (response.status, response.reason))
      if response.status not in (200, 302):
        log("Giving up")
        sys.exit(0)
      
  log("Starting '%s' VPN" % VPN_NAME)
  DBusGMainLoop(set_as_default=True)
  b = dbus.SystemBus()
  nm = b.get_object(NM_SERVICE, NM_VPN_PATH, True)
  interface = dbus.Interface(nm, NM_VPN_SERVICE)

  result = interface.getVPNConnections()
  # log(result)
  # log(interface.getVPNConnectionProperties(VPN_NAME))

  def ignore_callback(*args): pass
  
  result = interface.activateVPNConnection(VPN_NAME, dbus.Array([], 's'), 
    reply_handler=ignore_callback, error_handler=ignore_callback)
  # log(result)

try:
  doit()
except Exception, e:
  log("Exception: %s" % e)

sys.exit(0)