Crowd is a Web-based single sign-on (SSO) tool that simplifies application provisioning and identity management. It has connectors for popular open source projects like Apache (via Perl) and Subversion. Pre-built connectors for other popular commercial products like Jive Forums, JIRA, and Confluence are also available.
LemonLDAP::NG is a modular Web SSO based on Apache::Session modules. It simplifies the building of a protected area with a few changes in the application. It manages both authentication and authorization and provides headers for accounting, so you can have full AAA protection for your Web space. LemonLDAP::NG is a complete rewrite of LemonLDAP. All components needed to use it and to administer it are included in the tarball. However, all modules developed for LemonLDAP may not work with LemonLDAP::NG.