LDAP Tools/phpLDAPAdmin
From Authentication Tools for Joomla! (JAuthTools)
phpLDAPAdmin perhaps makes the most sense for users as they already have PHP and LDAP installed on their server. I use this personally on a server via the Debian package with a few configuration changes for my local setup. This is a more functional and large interface than the Java browser and is more conducive towards adding and editing entries.
For more information: http://phpldapadmin.sourceforge.net/