Drupal does not by default allow tracking slashes for pages and articles. Is it possible to enable trailing slash with a plugin?
You could hack the globalredirect module to undo its logic - add a trailing slash if it doesn't exist, leave it alone if it is.
As suggested by Nikit, this should be done by rewriting web servers.
There are several discussions about this at drupal.org . I would recommend switching to freenode and asking for #drupal.
Trailing Slash Module for Drupal 7:
http://drupal.org/project/trailing_slash
Perhaps the D6 version will be later.
Try the following: trailing slash URL