http://www.samba.org/samba/docs/man/Samba-HOWTO-Collection/winbind.html
http://www.enterprisenetworkingplanet.com/netos/article.php/3487081
http://us1.samba.org/samba/docs/man/Samba-HOWTO-Collection/domain-member.html
http://adldap.sourceforge.net/wiki/doku.php?id=mod_auth_ntlm_winbind
NOTE: I needed to add winbind enum users and winbind enum group to my smb.conf file for winbind to properly work.