Definindo o campo DecimalField no formato 0,00

currencyfield.py

# -*- coding: utf8 -*-

"""
Script baseado no snippet abaixo:
http://djangosnippets.org/snippets/176/

Obs.: Alterei algumas coisas como:
  * Import newsform para forms;
  * Aceitar o formato 0,00, sendo que o formato 0.00 é aceitado por padrão.
"""

import re
from django import forms

class CurrencyField (forms.RegexField):
    currencyRe = re.compile(r'^[0-9]{1,5}(,[0-9][0-9])?$')
    def __init__(self, *args, **kwargs):
        super(CurrencyField, self).__init__(
            self.currencyRe, None, None, *args, **kwargs)

    def clean(self, value):
        value = super(CurrencyField, self).clean(value)
        if value.replace(",", "."):
            new_value = value.replace(",", ".")
        return float(new_value)

class CurrencyInput (forms.TextInput):
    def render(self, name, value, attrs=None):
        if value != '':
            try:
                value = u"%.2f" % value
            except TypeError:
                pass
        return super(CurrencyInput, self).render(name, value, attrs)

form.py

# -*- coding: utf8 -*-

from django import forms

from utils.currencyfields import CurrencyField, CurrencyInput

class MyForm (forms.Form):
    amount = CurrencyField(widget=CurrencyInput, initial=0) # 0.00