Find out in what /dev is your cd-rom:
drutil status Vendor Product Rev MATSHITA DVD-R UJ-825 DAM5 Type: CD-ROM Name: /dev/disk1 Cur Write: 16x CD Sessions: 1 Max Write: 16x CD Tracks: 3 Overwritable: 00:00:00 blocks: 0 / 0.00MB / 0.00MiB Space Free: 00:00:00 blocks: 0 / 0.00MB / 0.00MiB Space Used: 66:55:27 blocks: 301152 / 616.76MB / 588.19MiB Writability:
So /dev/disk1 is or cd-rom now to make the ISO just run:
dd if=/dev/disk1 of=file.iso