If you want to authenticate Linux to a corporate network look at eDirectory as a corporate directory. It has many advantages over AD including partitioning, replication and synchronization. Check it out. With nSure Resource you can even sync your AD, MS Domains, LDAP, Exchange, Notes, SAP, Peoplesoft, SQL, LDAP and ... Password and accounts. Imaging enabling and disabling accounts at one location.
Remember eDirectory works with and on:
Microsoft Windows NT 4.0
Microsoft Windows 2000 Server and Advanced Server
Novell NetWare 5.x and 6
I would say it is complete Corporate Network and not just limited to Windows.
Hope this isn't too nit picky:-)