No doubt this is a very stupid question, but how do I mount the installation DVD?

I can't for the life of me figure out how to use the OS X cli mount application--doesn't seem to work like those for other *NIX systems I've used, since every time I try to mount something using it I get a permission denied error, even when I'm running as root.

I've discovered the Disk Utility application, but it won't mount the installation DVD either.....

It's not really a big issue, I booted the installation DVD and copied the kext I required, but for future reference I'd like to know how I can mount the Zephyroth installation DVD.

Thanks :-)