Although not yet widely implemented, LDAP should eventually make it possible for almost any application running on virtually any computer platform to obtain directory information, such as email addresses and public keys. Because LDAP is an open protocol, applications need not worry about the type of server hosting the directory.

An introduction to directories and X.500
Contains an overview of directories with specific emphasis on the X.500 directory architecture. Also provides information on the LDAP standard and links to related information about directories, the X.500 standard, and directory services.

An LDAP Roadmap and FAQ
Presents an annotated tutorial roadmap of LDAP documents and resources, including information about the IETF's directory service efforts, links to implementations, and links to existing LDAP/X.500-based directories.

Yahoo!'s LDAP page
Yahoo!'s directory of LDAP.

LDAP 101: Glue Your Network's Pieces Together
'The protocol nobody ever heard of' is gluing networks together with fast, flexible directory services and single sign-on for hassled users.

LDAP resources
Contains links to LDAP news items, overview documents, client, gateway and server software, mailing list information, and related Web resources.

RFC 1777
Request for Comments document for Lightweight Directory Access Protocol (LDAP).