ISOLabel
Change volume label on ISO 9660 image and Joliet extension
isolabel is a program that allows you to change volume label in ISO 9660 image file after it was already created.
Moreover, you can specify ISO 9660 and Joliet volume label separately, taking advantage of fancy names in Joliet together with simpler, but longer name in ISO 9660; something that tools like mkisofs/genisoimage does not allow you to do in standard compliant way.
This program is written to have minimal software dependency, and work on all platforms.