Index: django/db/models/fields/__init__.py
===================================================================
--- django/db/models/fields/__init__.py	(revision 7363)
+++ django/db/models/fields/__init__.py	(working copy)
@@ -490,6 +490,10 @@
 
     def formfield(self, **kwargs):
         defaults = {'max_length': self.max_length}
+        if self._choices:
+            defaults['form_class'] = forms.ChoiceField
+            defaults['choices'] = self._choices
+            del defaults['max_length']
         defaults.update(kwargs)
         return super(CharField, self).formfield(**defaults)