For Windows PC users.
The computer literate amongst you may not wish to read this 
I had no idea how to format a HDD as ext3 at all, and some of the online guides frightened the life out of me - so I asked a few questions of people in the know, and found this to be an easy, if long winded way of achieving the aim.
Download and create a Linux live cd. I used Ubuntu and found this useful guide. Note: It is a large download.
Once you have created this, put disc into PC and restart.
PC will now boot to ubuntu - this may take a few moments.
When presented with the options, select language, and Try Ubuntu.
Wait for Ubuntu graphical interface to load - this may take a few moments. When complete select:
System
Administration
GParted Partition Editor
A window appears on screen and in the main part lists the current HDD/Partitions.
Important - Make a note of these as they are system devices, and you do not want to make changes to them.
Connect your USB HDD/Pendrive.
Select:
GParted
Refresh Devices
At the top right of window select the down arrow, your connected device should now be listed as eg /dev/sdf - click on this.
The details of your USB device should appear in main window.
Highlight the FAT32/NTFS partition, and right click, highlight Format to and ext3, and click.
Details of pending operations can be viewed in the bottom pane
eg - Format/dev/sdf as ext 3
top of the window click on the Green Arrow, a confirmation dialogue box will appear, select apply.
Format starts, and the duration will depend on the size of the usb HDD/Pendrive you connected.
Once complete, close dialogue box.
At top right of screen click on power icon, and select restart, confirm restart.
Remove Live cd when prompted, and press enter, disconnect your usb HDD/Pendrive.
PC will now boot to windows.
