It's easy. I hooked up a dvd player to the P1 Jr. pico projector, and it worked just fine. All you have to do is plug in the AV cable, a mini-jack that on the other end has yellow (video), white and red (audio) female RCA jacks. Just hook up to a normal composite cable from you preferred device. In my case I used an Oppo DVD player. I plugged them in, selected AV input from the P1 Jr.'s main menu, and bingo - the movie appeared.
This image is missing it is from the first P1 Jr. tested. It will be posted within 24 hours.
I watched about 30 minutes of Road Trip on the P1 Jr. I set it up on a mini tripod, fired it at a screen, and it worked. I projected about a 30 inch diagonal image, in a fully dark room, and it was definitely watchable. I considered it a little dim, but in the dark room very acceptable considering the portability. In other words, you want to watch a movie on the side of your tent, while camping (no full moon please), or any other place you might find a 5 ounce projector ideal.
The image above was taken from Road Trip, with the first P1 Jr. that I worked with (from an early batch, I'm told). The one below, was taken with the newer P1 Jr. Of course the exposures are not identical, but.