Letterboxing my AVI file

Hello.

I'm working on a short film using my mini-DV camera (Panasonic 3CCD
GS-150). I'm having a problem with a tiny bit of vignetting when I'm
using my wide angle lens. I have to use it though because I am filming
in my apartment and many of the spaces are so tight, I need the wide
angle.

What I want to do is letterbox the resulting AVI/movie file. (I'm
using Windows XP). The camera has the ability to letterbox but I'm
mixing in still photos and possibly some video filters and sometimes
these creep over into the black area since they are part of the video
in reality.

So, how can I do this with software? I've got the following: Nero,
Panasonic Motion DV studio, Windows Movie Maker, and Pinnacle studio.
Pinnacle definitely has it as something you can buy as an add-on but
I've found that program very buggy so I don't use it and certainly
don't want to spend more on it.

My friend has Adobe Premiere and he thinks it will do it but he doesn't
know how.

Does anyone know how to do it with Premiere? Or perhaps a plug in for
one of the apps I myself have?

Many thanks,

-Will H