Index: django/contrib/localflavor/pl/forms.py
===================================================================
--- django/contrib/localflavor/pl/forms.py	(wersja 6397)
+++ django/contrib/localflavor/pl/forms.py	(kopia robocza)
@@ -6,6 +6,8 @@
 from django.newforms.fields import Select, RegexField
 from django.utils.translation import ugettext as _
 
+import re
+
 class PLVoivodeshipSelect(Select):
     """
     A select widget with list of Polish voivodeships (administrative provinces)
@@ -64,13 +66,85 @@
     """
     A form field that validates as Polish Tax Number (NIP).
     Valid forms are: XXX-XXX-YY-YY or XX-XX-YYY-YYY.
+
+    Checksum algorithm based on documentation at http://wipos.p.lodz.pl/zylla/ut/nip-rego.html
     """
+
+    def has_valid_checksum(self, number):
+        """
+        Calculates a checksum with the provided algorithm.
+        """
+        multiple_table = (6, 5, 7, 2, 3, 4, 5, 6, 7)
+        result = 0
+        for i in range(len(number)-1):
+            result += int(number[i])*multiple_table[i]
+
+        result %= 11
+
+        if result == int(number[-1]):
+            return True
+        else:
+            return False
+
     def __init__(self, *args, **kwargs):
         super(PLTaxNumberField, self).__init__(r'^\d{3}-\d{3}-\d{2}-\d{2}$|^\d{2}-\d{2}-\d{3}-\d{3}$',
             max_length=None, min_length=None,
             error_message=_(u'Enter a tax number field (NIP) in the format XXX-XXX-XX-XX or XX-XX-XXX-XXX.'),  *args, **kwargs)
 
+    def clean(self,value):
+        super(PLTaxNumberField, self).clean(value)
+        value = re.sub("[-]","",value)
+        if not self.has_valid_checksum(value):
+            raise ValidationError(_(u'Wrong checksum for the Tax Number (NIP).'))
+        return u'%s' % value
 
+class PLNationalBusinessRegisterField(RegexField):
+    """ 
+    A form field that validated as Polish National Official Business Register Number (REGON)
+    Valid forms are: 7 or 9 digits number
+
+    More on the field: http://www.stat.gov.pl/bip/regon_ENG_HTML.htm
+
+    The checksum algorithm is documented at http://wipos.p.lodz.pl/zylla/ut/nip-rego.html
+    """
+    
+    def has_valid_checksum(self, number):
+        """
+        Calculates a checksum with the provided algorithm.
+        """
+        multiple_table_7 = (2, 3, 4, 5, 6, 7)
+        multiple_table_9 = (8, 9, 2, 3, 4, 5, 6, 7)
+        result = 0
+        
+        if len(number) == 7:
+            multiple_table = multiple_table_7
+        else:
+            multiple_table = multiple_table_9
+
+        for i in range(len(number)-1):
+            result += int(number[i])*multiple_table[i]
+
+        result %= 11
+
+        if result == 10:
+            result = 0
+
+        if result  == int(number[-1]):
+            return True
+        else:
+            return False
+
+    def __init__(self, *args, **kwargs):
+        super(PLNationalBusinessRegisterField, self).__init__(r'^\d{7,9}$',
+            max_length=None, min_length=None, error_message=_(u'National Business Register Number (REGON) consists of 7 or 9 digits.'),
+            *args, **kwargs)
+    
+    def clean(self,value):
+        super(PLNationalBusinessRegisterField, self).clean(value)
+        if not self.has_valid_checksum(value):
+            raise ValidationError(_(u'Wrong checksum for the National Business Register Number (REGON).'))
+        return u'%s' % value
+
 class PLPostalCodeField(RegexField):
     """
     A form field that validates as Polish postal code.
Index: tests/regressiontests/forms/localflavor/pl.py
===================================================================
--- tests/regressiontests/forms/localflavor/pl.py	(wersja 6397)
+++ tests/regressiontests/forms/localflavor/pl.py	(kopia robocza)
@@ -35,11 +35,15 @@
 Traceback (most recent call last):
 ...
 ValidationError: [u'Enter a tax number field (NIP) in the format XXX-XXX-XX-XX or XX-XX-XXX-XXX.']
->>> f.clean('43-34-234-323')
-u'43-34-234-323'
->>> f.clean('433-344-24-23')
-u'433-344-24-23'
-
+>>> f.clean('64-62-414-124')
+u'6462414124'
+>>> f.clean('646-241-41-24')
+u'6462414124'
+>>> f.clean('646-241-41-23')
+Traceback (most recent call last):
+...
+ValidationError: [u'Wrong checksum for the Tax Number (NIP).']
+ 
 # PLNationalIdentificationNumberField ############################################
 
 >>> from django.contrib.localflavor.pl.forms import PLNationalIdentificationNumberField
@@ -58,4 +62,20 @@
 Traceback (most recent call last):
 ...
 ValidationError: [u'National Identification Number consists of 11 digits.']
+
+# PLNationalBusinessRegisterField ################################################
+
+>>> from django.contrib.localflavor.pl.forms import PLNationalBusinessRegisterField
+>>> f = PLNationalBusinessRegisterField()
+>>> f.clean('590096454')
+u'590096454'
+>>> f.clean('590096453')
+Traceback (most recent call last):
+...
+ValidationError: [u'Wrong checksum for the National Business Register Number (REGON).']
+>>> f.clean('590096')
+Traceback (most recent call last):
+...
+ValidationError: [u'National Business Register Number (REGON) consists of 7 or 9 digits.']
+
 """