Start by creating the file /etc/sysconfig/network-scripts/ifcfg-eth0:0 and the contents will read:
DEVICE=eth0:0
BOOTPROTO=static
IPADDR=YOUR NEW IP ADDRESS
NETMASK=255.255.255.255
ONBOOT=yes
Then, as root, run
/sbin/ifup eth0:0
Repeat that process for each additional IP address you have to configure, incrementing the :0 number each time. For instance, your second additional IP would be in the "ifcfg-eth0:1" file and the DEVICE= line would read "DEVICE=eth0:1". Your third additional IP would be eth0:2 and so on.
