I've tried various times to recreate this effect, using things like the venetian blinds transition, the CC Balls filter and even creating an image with a repeating black grid-like pattern. The best results I got came when I set my camcorder to Ski/winter mode and filmed the footage through my CRT TV.
Graham's approach is definitely the most realistic, but in case your cam doesn't have that kind of setting, you could also make a file in Photoshop with alternating lines of dark and lighter grey to simulate TV fields. Add some noise or grain. And use a bullnose mask so the edges aren't a sharp rectangle. Then, lay it over your footage in AE using a blending mode of your choice ... I forget which works best, but maybe screen or add with slightly lowered opacity so that it also simulates the slight glow of a TV screen. While there are better methods (some using third-party plugins), this method renders pretty quickly so it just depends on your specific needs/preferences.