In Virtualization everything is virtual, so if you are planning for a virtual machine installation. it will be easy for you to make a iso image from cd/dvd and mount it as a virtual cdrom..
in linux dd command can do this things ..
This is an Example :
[root@vps ~]# dd if=/dev/cdrom of=xp.iso
dd command will make a xp.iso image file from physical cdrom..