Sure, you will find the “scale” slider under Effects Control > Motion. Make sure you start with a standard DV project. Playing with the scale slider, you just want to fill the frame.
By the way, I meant “zooming in”. There will be a slight loss in quality; no way around it.
Again, I would try to convince them to stick with 16:9, they’ll regret the 4:3 decision as soon as they get that widescreen 😉
Vince