Make a new comp with horizontal & vertical dimensions one-third of normal.
Add the footage to to the comp and scale it to fit the comp.
Make a comp in the normal dimensions.
Add the footage.
Scale it to fit the comp.
You're ready for the final render.
Former Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Dave's suggestion is a way to go, however if you will loose resolution overall. If it's just the crisp look that bothers you but you still want smooth edges and not jaggy pixels, you can soften the image by adding noise or grain and/or applying a small channel blur (blue works best in most situations).