From the website:

he Apache Directory Server is an embeddable LDAP server written in Java. It has been designed to introduce triggers, stored procedures, queues and views to the world of LDAP which has lacked these rich constructs. 

JXplorer is an open source ldap browser originally developed by Computer Associates' eTrust Directory development lab. It is a standards compliant general purpose ldap browser that can be used to read and search any ldap directory, or any X500 directory with an ldap interface. It is available for immediate free download under a standard OSI-style open source licence.