get the o'reilly ldap book
I used the O'Reilly LDAP book to build my first test LDAP account management environment. It walks through the entire process, step by step, letting you build a working example of what you need.
I wrote a perl program to add/modify/delete entries in our login account/group database, and another to manage the sendmail aliases database, all of which is stored on a pair of replicated OpenLDAP servers.
The only thing I did differently than the LDAP book is to use SSL/TLS certificate authentication/encryption, so passwords aren't flying across the net in plain text and spoofing our LDAP servers is much harder.
The only problem I've run into with using LDAP accounts, is that the stable CVS network daemon doesn't support LDAP accounts (yet), and there is a bug in SUDO with LDAP accounts, which I reported and is apparently fixed in the next release.
Oh, and the steep learning curve. Learning LDAP from scratch can be brutal.