The following resources offer additional information on LDAP. It is highly recommended that you review these, especially the OpenLDAP website and the LDAP HOWTO, before configuring LDAP on your system(s).
/usr/share/docs/openldap-<versionnumber>/ directory — Contains a general README document and miscellaneous information.
LDAP related man pages — There are a number of man pages for the various applications and configuration files involved with LDAP. The following is a list of some of the more important man pages.
man ldapadd — Describes how to add entries to an LDAP directory.
man ldapdelete — Describes how to delete entries within an LDAP directory.
man ldapmodify — Describes how to modify entries within an LDAP directory.
man ldapsearch — Describes how to search for entries within an LDAP directory.
man ldappasswd — Describes how to set or change the password of an LDAP user.
man ldapcompare — Desribes how to use the ldapcompare tool.
man ldapwhoami — Describes how to use the ldapwhoami tool.
man ldapmodrdn — Describes how to modify the RDNs of entries.
man slapd — Describes command line options for the LDAP server.
man slurpd — Describes command line options for the LDAP replication server.
man slapadd — Describes command line options used to add entries to a slapd database.
man slapcat — Describes command line options used to generate an LDIF file from a slapd database.
man slapindex — Describes command line options used to regenerate an index based upon the contents of a slapd database.
man slappasswd — Describes command line options used to generate user passwords for LDAP directories.
man ldap.conf — Describes the format and options available within the configuration file for LDAP clients.
man slapd.conf — Describes the format and options available within the configuration file referenced by both the LDAP server applications (slapd and slurpd) and the LDAP administrative tools (slapadd, slapcat, and slapindex).
http://www.openldap.org/ — Home of the OpenLDAP Project. This website contains a wealth of information about configuring OpenLDAP as well as a future roadmap and version changes.
http://www.padl.com/ — Developers of nss_ldap and pam_ldap, among other useful LDAP tools.
http://www.kingsmountain.com/ldapRoadmap.shtml — Jeff Hodges' LDAP Road Map contains links to several useful FAQs and emerging news concerning the LDAP protocol.
http://www.ldapman.org/articles/ — Articles that offer a good introduction to LDAP, including methods to design a directory tree and customizing directory structures.