Some initial work has been contributed by desiv on atutor.ca, writing the code to allow ATutor to authenticate against an external LDAP directory server. The goal of this project is to create a general adaptor adapter that will authenticate users against any directory service, in addition to current LDAP support.
We have not yet tested the code, but all accounts indicate it works fine for authenticating against an LDAP directory.
ATutor changed or new files for LDAP
The ldap.php is the file from the OSU Helpdesk (which is OSS as well) that I have tweaked a bit to work here.
I added the LDAP specific configs there, except I put a LDAP define in config.inc.php with an include if defined.
This way, you can turn the LDAP define to 0 and it uses the local database and the original screens.
If you set it for 1, it tries to use LDAP authentication (except for the Admin user created with the ATutor install).
I've done some basic testing and it's working well so far, but we haven't gone production yet.