We released version 1.0 of the Kerberos iRODS authentication plugin this morning.
Tested packages for Ubuntu 10 and 12, SuSE 11 and 12, and CentOS 5 and 6 can be found at ftp://ftp.renci.org/pub/irods/plugins/irods_auth_plugin_krb/1.0/.
Please confirm the checksums for the package(s) you download before installing.
The code is open source and available, along with a README:
As always, please contact firstname.lastname@example.org if you have any questions.