The title says it all but I've made a bit of a mess of this. I have tried Gmount but it asks for a password (no idea what this is). I then tried Furious, which really isn't intuitive. After that I tried MountManager, which scared the hell out of me.
I'd just like to mount an ISO onto my USB stick (this is to install Ubuntu on my father's machine cos I'm pretty impressed with it and he is hating Windows 7) so I can boot from the stick.