Install gmountiso in Ubuntu
sudo aptitude install gmountiso
This will complete the installation.
If you want to open go to Applications--->System Tools--->Gmount-iso
Once it opens you should see the following screen here you can specify your .iso file and mount point where you want to mount.
Example for gmountiso
I am having dsl-4.0.iso image on my desktop and i want to mount this under dsl directory so i have menctioned all the details and click on mount
This will prompt for root password enter your root password and click on ok
Once it finished mounting you can see these details under mounted images
You can see the files and folders inside dsl directory
If you want to unmount just select the your mount point and click on Unmount
This is very simple and easy process.