The console-over-serial seems to be set up by default, so you can do all the fancy POST things that you might want to do. Serial-console-over-ethernet is not set up by default and right now I don't know how to do it.
Instructions Specific to CentOS 4 the V60x
Add to /etc/grub.conf
serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal --timeout=10 serial console
Add to all your kernel
lines in /etc/grub.conf:
If you do this, the first time you boot the OS will offer to set things up for you to work with a serial console.