class MeuModel(Model):

  nome = model.CharField('Nome', max_length=80)

  def _edicao(self):
    return '''<a href="#" onclick="alert('Ok');">Acao</a>''';

  _edicao.short_description = u'Edição'
  _edicao.allow_tags = True


#O Admin
class MeuAdmin(admin.ModelAdmin):
  fields = ('nome','_edicao',)