Drupal provides a logout link for authenticated users, but does not provide a login link for anonymous users. This module provides that.
This handles issue http://drupal.org/node/74706
Notes for Drupal 6
This module is not needed in Drupal 6. To get the same functionality, go to '/admin/build/menu-customize/navigation' and click "Add Item". Use the following:
Menu link title: Log in