Assuming:

• Redhat Enterprise Linux 5.x
• Virtual Machine Manager

Do it now:

• Open Virtual Machine Manager
• Select the VM
• Select Details
• Select the Hardware tab
• Select Add
• Select select select…say CLICK damn it!
• Choose Storage
• Select File-based
• Browse to or enter the path of the *.iso disc image
• Hit the rest of the buttons in the wizard…you’ll make it on your own; I promise^*.

<Intermission>

Continue on:

• Open the VM’s configuration file (usually in: /etc/xen/) in your text editor of choice
• Change the ‘boot=’ line to ‘boot=”d”‘
• Edit the portion of config file that specifies the new storage device. Change “hdx” to “ioemu:hdx:cdrom”.

^*You may suck. Promise not legally binding.