In order to get pretty good results, try this. If your animation is 640x480, export it to 1440x1080 instead. Then open it in VirtualDub. Select the resize filter. Type in 720x480 (non sqaure pixel for tv) and be sure to set the "Filter Mode" to "Precise Bilinear". Now select "OK". Now in order to see the results, either press the play or next button.
Try it out. It's the best method that I know of.
