I went to the fine folks at Google and I found a site that may be of some interest to you.
Click Here. It's called pam_smb and it's a NT authentication tool for Linux. Here's a link to the FAQ.

pam_smb is a PAM module/server which allows authentication of UNIX users using an NT server.
Features (stable version):

- Authenticates Linux users against SMB servers in user mode(95, NT, samba etc). Will not authenticate against share level systems.
- Compiles on Redhat Linux 4.2 and greater and any Linux with PAM support. Also compiles under Solaris 2.6.
Developement version from CVS works on HP/UX 11 and FreeBSD 3.1
- Supports NT/Lanman encrypted passwords.
- Any service which uses PAM can authenticate against NT.
- Can setup to ignore lack of a local password entry when something else provides the users information such as RADIUS.

Planned Features (development version):
Caching support.
Username mapping support of Unix usernames to different NT usernames.

Hope this helps,
Remote_Access_