forms.py

class CadastroUsuarioForm(forms.Form):
    cep = forms.IntegerField(widget=CEPInput(address={
        'street': 'id_endereco',
        'district': 'id_bairro',
        'city': 'id_cidade',
        'state': 'id_estado'
    },
        attrs={'class': 'cepMask', 'placeholder': 'CEP'}),
        help_text='Ao inserir o CEP, os dados de endereço serão preenchidos automaticamente.')
      
    endereco = forms.CharField(max_length=255, label='Endereço',
                               widget=forms.TextInput(attrs={'placeholder': 'Endereço'}))
    numero = forms.IntegerField(label='Número',
                                widget=forms.TextInput(attrs={'class': 'numeroEnderecoMask',  'placeholder': 'Número'}))
    complemento = forms.CharField(max_length=255, required=False,
                                  widget=forms.TextInput(attrs={'placeholder': 'Complemento'}))
    bairro = forms.CharField(max_length=255, widget=forms.TextInput(attrs={'placeholder': 'Bairro'}))
    cidade = forms.CharField(max_length=255, widget=forms.TextInput(attrs={'placeholder': 'Cidade'}))
    estado = BRStateChoiceField(widget=forms.TextInput(attrs={'placeholder': 'Estado'}))

signup.html

{% extends "base_site_simples.html" %}

{% block head %}
    {% load staticfiles %}
    <script type="text/javascript" src="{% static 'tesportessite/jquery-1.8.2.min.js' %}"></script>
    <script type="text/javascript" src="{% static 'tesportessite/jquery-ui-1.10.4.min.js' %}"></script>
    <script type="text/javascript" src="{% static 'tesportessite/jquery.mask.min.js' %}"></script>
    <link rel="stylesheet" href="{% static 'tesportessite/jquery-ui-1.10.4.custom.css' %}"></link>


    <script type="text/javascript">

        function unmask(){
            $('.cepMask').unmask();
        };

        $(function() {
            $('.cepMask').mask('00000-000');

        });

         $(document).ready(function(){
            $(".zip-field").blur(function(){
                var arr;
                // validates CEP
                var regex = /^([0-9]{5})[-. ]?([0-9]{3})$/;
                if (regex.test($(".zip-field").val()))
                {
                    $.get('/cep/'+$(".zip-field").val()+'/', function(data,status)
                    {
                        eval("var arr = "+data);
                        $("#"+address.street).val(arr.street);
                        $("#"+address.district).val(arr.district);
                        $("#"+address.city).val(arr.city);
                        $("#"+address.state).val(arr.state);
                    });
                }
            });
        });

    </script>



{% endblock head %}


{% block content %}


<form class="signup cadastro_usuario" id="signup_form" method="post" action="{% url 'account_signup' %}">
    {% csrf_token %}
        {% for field in form %}
            
                <div id="p_{{ field.id_for_label }}" class="field_wrapper">
                    <p>
                        <span>{{ field }}</span>
                    </p>
                    <p class="help-text">
                        {{ field.help_text }}
                    </p>
                    <p class="help-text">
                        <span class="field_error_message">{{ field.errors|striptags }}</span>
                    </p>
                </div>
        {% endfor %}

  <button type="submit"  value="Cadastrar" onclick="unmask();" >Cadastrar</button>

</form>


{% endblock %}

urls.py

# coding=utf-8
from django.conf import settings
from django.conf.urls import patterns, include, url
from django.conf.urls.static import static

from django.contrib import admin

admin.autodiscover()

#Site e Admin
urlpatterns = patterns('',

    url(r'^admin/', include(admin.site.urls)),

    url(r'^', include('site.urls')),

    #django-cep
    url(r'^cep/', include('cep.urls')),


)