This is the one stop dashboard for all things Kerberos at JBoss.
What project should I look for Kerberos support in JBoss?
JBoss Negotiation ( a sub project of PicketLink)
This link also has some great information on various projects at JBoss that have started Kerberos support.
The user guide is attached in pdf format at the end of this article.
How do I set up a KDC to operate with JBoss?
Please refer to the setting up kerberos dev environment article. (Courtesy: Sohil Shah, GateIn)
What KDC should I look for?
Windows Environment: There should be windows domain controllers for Win 2000, 2008 etc. Also look at Active Directory documentation.
Unix/Linux Environment: Look above in the setting kerberos dev environment link.
Mac Environment: Same as Unix Environment above.
Can I use Kerberos for EJB3s?
Please refer to the EJB3 Authentication With SPNEGO article.