AS of 2003 functional level domains running server 2008 machines only, you can rename the domain controllers with netdom.
for 2003 and below domain controllers, there are other articles helping you out that meet that need.
Run the following command
NETDOM computername oldcomputername.local /add:newcomputername.local
Make sure DNS propagation is up to date with the new name then run
NETDOM computername oldcomputername.local /makeprimary:newcomputername.local
you will need to reboot the DC now to apply that change.
then remove the old name
NETDOM computername newcomputername.local /remove:oldcomputername.local