OpenLDAP is installed by default on Tiger (and earlier versions of OS X). In order to get it into a useful state, however, you will need to make a few changes:
Locate the OpenLDAP configuration files in /etc/openldap/
cp slapd.conf.default slapd.conf
Edit slapd.conf:
database netinfo suffix "" flags DSENGINE_FLAGS_NATIVE_AUTHORIZATION datasource /var/db/netinfo/network.nidb include /etc/openldap/schema/netinfo.schema
And add the following:
database bdb directory /var/db/openldap/openldap-data/ suffix "dc=hccp,dc=org" rootdn "cn=Directory Manager,dc=hccp,dc=org" rootpw secret
(optionally use slappasswd to avoid plaintext password in slapd.conf)
Make sure that /var/db/openldap/openldap-data/ exists, creating it if it does not.
Run slapd: sudo /usr/libexec/slapd