http://www.zenphoto.org/2009/11/user_logout/

the Usage information link for this plugin doesn't take you to a page of info. how can i find out how to put a LOGIN box in my template?

The correct link is here: http://www.zenphoto.org/documentation/plugins/_zp-extensions---user_login-out.php.html

The link must not have been updated since the name of the plugin was changed.... You can always look through the Functions Documentation in the User Guide to find the correct link.