How to run UNetBootin (or similar) on Linux?

The easy way to install unetbootin is through software center (in Linux Mint 14 or later it is called Software Manager).

From the command line something like sudo apt-get install unetbootin would be the easiest way. If you are not comfortable with the command line then using the synaptic package manager on Ubuntu or the Software Center would be the best choices using a GUI.