This is a simple patch for py-googlemaps (sourceforge.net/projects/py-googlemaps/). It's incomplete but just it works with the Google Maps API v3 if you have to patch an old existing application that uses the address_to_latlng method.

py-googlemaps

# v3 api
from googlemaps import GoogleMaps
from googlemaps import GoogleMapsError
from googlemaps import fetch_json

GoogleMaps._GEOCODE_QUERY_URL = 'http://maps.googleapis.com/maps/api/geocode/json?'

def geocode(self, query, sensor='false', oe='utf8', ll='', spn='', gl=''):
    if (ll is None and spn is not None) or (ll is not None and spn is None):
        raise GoogleMapsError('Both ll and spn must be provided.')
    params = {
        'address':        query,
#        'key':      self.api_key,
        'sensor':   sensor,
#        'output':   'json',
#        'oe':       oe,
#        'll':       ll,
#        'spn':      spn,
#        'gl':       gl,
    }
    url, response = fetch_json(self._GEOCODE_QUERY_URL, params=params)
    status_code = response['status']
    if status_code != u'OK':
        raise GoogleMapsError(status_code, url, response)
    return response

GoogleMaps.geocode = geocode

def address_to_latlng(self, address):
    location = self.geocode(address)['results'][0]['geometry']['location']
    return (location['lat'], location['lng'])
    #return tuple(self.geocode(address)['Placemark'][0]['Point']['coordinates'][1::-1])

GoogleMaps.address_to_latlng = address_to_latlng