Fine-grained authorizations and single sign-on for SSH remote commands
apache cookie SSO mechanism.
Apache LDAP Directory Manager
gnupasswd - gnu change user password
Plugin for OpenLDAP who checks password quality
Project moved to github: https://github.com/pam-pgsql/pam-pgsql
Authentication, Access Control, and Single Sign-On
Open Source Web Single Sign-On
pGina is an open source replacement authentication system for Windows