An "iso" is an image of a disk, so use that as the source when burning the contents to cdrom. I mean, use an option like "burn from image" and select the iso, not to burn the iso "as is", then you'll have a 1-file coaster. Cdrom 1 will be bootable. Select "boot from cdrom" in your BIOS, pop in the cd and off you go...
I think you could also extract the disks using some freeware tool, and use the contents and a bootdisk to start up the installer, but having the cd's can come in handy later.