As of Ubuntu 8.10 a utility has being included within Ubuntu to aid in doing this, so this time there will be no command line needed.
Before you begin you need to now that you will need a USB Pendrive that is at least 1 Gigabyte in size, you will also need the Ubuntu iso image downloaded. It is also important to note that any data on the pen drive will be destroyed, so backup anything you want...
Right so the first thing you need to do is start the application, which is in System->Administration and is called USB Startup Disk Creator.
Now that you have done this it will ask you to enter your password. Once you have entered your password the following screen will be displayed
You now need to tell it where the iso image is, tho do this click the Other button, this will bring up the following screen.
Now that you have selected the iso image it will return you to the screen with the details filled in, as shown below:
Now you need to specify how much of the disk you want to use for persistent storage, this is done by moving the slider to the right as shown below:
Once you have done that you can click the Make Startup Disk button at the bottom right, this will display the following screen:
It is now making the USB stick, this may take a while, once completed it will display the following message:
Well thats it you now have a bootable persistent Ubuntu pen drive.
NOTE: To use the pen stick you have to make sure that the computer you are trying to boot it with has the settings in the BIOS set to boot from USB devices.
------------------------------------------ NOTE: These articles are tutorials/general ramblings. I do not except responsibility for anything that goes wrong, be it a broken HDD, an entire computer or if you chop off your arms, follow anything I say on this site at your own risk.
------------------------------------------