I had written an article for [The Delphi Magazine] way back when..... if you have access to a backlog of those magazines, it's in issue no. 62 (October 2000) - unfortunately, it seems those back issues aren't available for purchase anymore :-(
It's too long of an article and a code sample to post here.... basically it's about wrapping the IDirectorySearch interface in a nicer Delphi-like shell. You pass in a base container where to search, you define an LDAP filter, and you define a set of attributes you're interested in - then you search and get back basically an enumerator for the results, which you can get one by one.