Hi,
What platform are you looking for a binary on?
OpenLDAP comes with most recent Linux distributions. Sun One Directory Server is free to use up to 250,000 users on Solaris 9. Novell and IBM both have binary servers available on some platforms (though IBM's server may no longer be free and Novell has a maximum number of entries before you have to license, I believe). If you've already licensed BEA WebLogic, it includes the 100%
Java LDAP server that my company develops.
Clayton