Hello Craig,


I can't this to work either.  Are you supposed to just be able to login
via gdm with an AD account or do the local users matching the AD users
still have to be set up?


Here is a link to the Likewise Open section of the Server Guide that will be released with Hardy [1].  You will probably also need to edit /etc/nsswitch.conf as mentioned by Alexpacio. 

[1] http://doc.ubuntu.com/ubuntu/serverguide/C/likewise-open.html

--
Party On,
Adam