If you are using centos in a virtual machine or a local machine you may want to change to console resolution so that you see more than 80×25 screen. For this, you need to modify the kernel line.

vi /boot/grub/grub.conf

add/change vga parameter

kernel /vmlinuz-2.6.18-8.el5 ro root=LABEL=/ vga=0x31A

reboot
That will set the resolution to 1280×1024. For a list of possible vga codes see http://wiki.antlinux.com/pmwiki.php?n=HowTos.VgaModes