Here is a guide to install Gmount-iso on Ubuntu 13.04. You can install Gmount-iso using the Ubuntu Software Center.
Gmount-iso is a small tool written using PyGTK and Glade. It allows you to easily mount your cd images. This is a frontend to the ‘mount -o loop -t iso9660 foo.iso /mountpoint’ command. Visit the Gmount-iso Homepage.
To install Gmount-iso click on the link below
When the software center is opened click on the Install button and enter your password to authenticate the installation. When Gmount-iso is installed you can close the software center, to start Gmount-iso press the SuperKey and type: gmount
How to open the apt link? Read this article.