Apache Directory Studio - Apache Directory Studio is a complete directory tooling platform intended to be used with any LDAP...
NethServer - NethServer is an operating system for Linux enthusiasts, designed for small offices and medium...
Ldap Admin - Ldap Admin is free Win32 administration tool for LDAP directory management.
ClearOS - A very good alternative for Windows Server, for free
LDAP Tool Box White Pages - Simple web interface to search and display information form an LDAP directory
Univention Corporate Server - Univention Corporate Server UCS with Active Directory functions and App Center is the cost-efficient and popular successor to Microsoft's server solutions.