You'll have to use Samba(this is assuming, of course, that the computer in question is going a file server). I believe
www.freeos.com has a couple of articles on making Samba file servers part of a domain. This will allow you to give domain permissions to the files on the server in the Samba share
If a file server is not what you have in mind, you will probably experience a lot of frustration. A Linux/Unix computer cannot log into an Active Directory domain. Active Directory does not play well with the Unix shells. Of course, if you aren't going to create a file server, then you wouldn't really need for it to be part of the domain.
