#1 install mgetty
rpm -ivh mgetty-1.1.26-6.rpm

#2 add to /etc/inittab file
S0:12345:respawn:/sbin/mgetty ttyS0
S1:12345:respawn:/sbin/mgetty ttyS1

Where S1 and ttyS1 is for COM Port 2
and S0 and ttyS0 is for COM port 1

#3 Edit mgetty.config under /etc/mgetty+sendfax
port ttyS0
  direct y
  speed 115200
  data-only y
port ttyS1
  direct y
  speed 115200
  data-only y

Optional Steps
For lilo
To see boot messages at boot edit lilo.conf

append="console=ttyS1,9600n8 console=tty0"

Example:
image=/boot/vmlinuz-2.4.18-3
        label=serial
        initrd=/boot/initrd-2.4.18-3.img
        read-only
        root=/dev/hda2
        append="console=ttyS1,9600n8 console=tty0"

For grub
#boot=/dev/hda
serial --unit=0 --speed=9600
terminal --timeout=10 serial console
default=0
timeout=10
#splashimage=(hd0,0)/boot/grub/splash.xpm.gz
title Red Hat Linux (2.4.18-10)
        root (hd0,0)
        kernel /boot/vmlinuz-2.4.18-10 ro root=/dev/hda1 console=tty0 console=ttyS0,115200n8


To be able to log in as root add ttyS0 and/or ttyS1 
to the /etc/securetty file

Install lrzsz-0.12.20-12.i386.rpm if you want to be 
able to do file transfers.