Two Kerberos implementations are availble. One is from MIT, web.mit.edu/kerberos/dist, and the other, Heimdal, is available from KTH in Sweden at www.pdc.kth.se/heimdal.
pam_krb5_migrate: freshmeat.net/projects/pam_krb5_migrate
pam_krb5: sourceforge.net/projects/pam-krb5
The MIT Kerberos 5 distribution comes with good documentation about installing, administrating and using Kerberos. The recently published O'Reilly book Kerberos: The Definitive Guide by Jason Garman (ISBN 0-596-00403-6) is a good resource for setting up a new realm and getting interoperability with other operating systems to work.
Using Microsoft Active Directory with Kerberos clients: www.microsoft.com/windows2000/techinfo/planning/security/kerbsteps.asp.
