If you were to show that on a widescreen monitor the image would get squeezed, widescreen is a resolution which cannot be achieved by putting a black border on top of your movie.
There's 3 ways of doing it:
1. Record in a 16:9 widescreen resolution (1280x720 anyone? ) and render it in the same resolution.
2. Render your movie in a 16:9 resolution though your recordings are in 4:3 (remember to change aspect ratio).
3. Crop enough pixels from 4:3 to make it fit 16:9
800 / 600 = 1.33:1
1280 / 720 = 1.78:1
If you try to watch a 800x600 movie on a widescreen monitor like for instance 1920x1200 monitor it will of course get upscaled to fit the screen but since the monitor fits a 1.60:1 AR movie max and can't go further down from that you will have it in 1600x1200 and black bars at the sides.
Write a widescreen tutorial that's actually working, locked... thanks for trying though.