There are several ways. The most elegant way is using winbind, but you'll have to join your Linux host to the domain (requires a domain admin priv user to do an operation from your Linux host).
See:
http://us1.samba.org/samba/docs/man/Samba-Guide/
On the cheap side, you can use pam_smb (NTLM style).
I'm talking here about the ability to either login or access resources using your AD password... it can get quite complicated if you want GSSAPI support. For me it's enough to load SSH keys on domain login and just bounce to the various Linux hosts for login without passwords (cheap man's single sign-on).
