In the past four years, my operation system was BSD. Somebody suggested me to try Ubuntu, but I had no idea for it. Today, my system was broken, so I decided to install it to my computer.
But I had any drivers of cdrom, I must install it without CD/DVD.
My method is very simple.
sudo vi /boot/grub/menu.lst
title Ubuntu 8.04 LiveCD
kernel /vmlinuz boot=casper iso-scan/filename=/Ubuntu-8.04-desktop-i386.iso quiet splash ro locale=zh_CN.UTF-8
Of course, if you have one copy of windows, you should unpack iso to a partation of msdos, and then run installer...