If it's the same as Premiere 6.0, you have to use the "clip" effect, in P' 6.0 it's right next to the "crop" effect in the video effects > Transform menu I think. This will put borders on top of the frame rather than stretching the frame to fit the screen.
Set the top and bottom values to whatever looks nicest, obviously keep them the same, and set the background colour to black.
That'll give you the wide-screen viewed on regular TV look.
If you want to change it to 16:9 footage, so you can view it properly on a wide-screen TV then look at these threads/articles:
A Thread in the Premiere Forum www.marcpeters.co.uk/convert-4-3-to-16-9