NTSC 16:9 widescress will look like 4:3 with tall skinny people. The reason for this is that a 16:9 NTSC monitor streches the picture sideways to fill the screen.
You may have noticed that some people who have 16:9 TV’s always have short fat people on the screen. That’s beacuse they are stretching a 4:3 image sideways to fill the screen.
If you are rendering an MPEG 2 for DVD, just select NTSC widescreen and it will render out for NTSC (Note in Vegas you need to select include audio on the audio tab. DVDA defaults to include audio). Your DVD player should letter box the signal or play it full screen depending on your set up. You will need to make sure that your DVD player and TV are also set for widescreen.
If you are rendering as a WIndows Media file, Real Media, or Quicktime, you want to choose a 16:9 format or you may want to consider choosing a custom size to render to, like 640 x 360.