how to mount *.iso files?

I'm sorry to say that I can't type chinese words by computer,so I had to use English!
My question is how can I mount a *.iso file, and the file is the install *,iso file of fedora core 4. when I want to install gcc*.rpm from it and computer ask me to insert the install disk, but i installed the os from hard-disk,so i want to know how to deel with this problem?
Thanks very much!

mount -t iso9660 -o loop xxx.iso /mnt

要是挂载DVD的ISO来添加和安装程序可能会有问题，反正我的已经挂载还是提示没有盘，我只好手动安装想要装的程序。