Thanks for your replies.
To add to my confusion I'm in Britain so I'm after PAL settings rather than NTSC, but surely the screen dimensions are the same?
The export settings that I've used so far are
Format: Quicktime
Preset: PAL DV Widescreen
Video Codec: DV PAL
With these settings I am not able to alter the width and height as they are greyed out and locked at 720x576. There is also no option anywhere I can see to change the PAR. The resulting video played in Quicktime Player (set to 'fullscreen') or VLC fills the screen vertically but has black bars to the left and right (See below).In the program monitor window in Premiere my footage fills the frame completely.
I simply want to export it as a widescreen Quicktime (or even an avi) but I still can't seem to work it out. It's driving me mad!
Thanks again for your help, it's greatly appreciated.