If you're a unix geek like me, it shouldn't be too much of a problem. AD is a marketing name for an
LDAP implementation with a bunch of predefined schemas. Just like Novell's eDirectory.
If you've used LDAP before, get hold of a directory browser so you can see what the forest and tree structures look like, and what fields the leaf records have. Should be quite obvious at that point.
At any rate, search and ye shall find: the new search subsystem is great or you can search google with "site:moodle.org". Several people have posted their AD solutions and strategies.