LDAP basics

I am in the process of configuring an LDAP server to work with my pop server (MDaemon). I am trying to expand the functionality of the LDAP server but I don’t have a lot of knowledge on the subject. All I want to do is add attributes to the users that will allow me to add Company, Fax Number, and any other information that Outlook could pull from it. Any help or a good wesite would be appreciated./