ConnersTutorials, teaches you how to put two videos playing simultaneously in one movie. You use Sony Vegas and drag both movies in the time-line below. Then you press Event pan/crop on the first video. Right click and choose Match output aspect. Then re-size and move the video as you want. Do the same for the other video. Go to Media Generators to choose the background, which can be a solid color, a picture or another video. Just drag that down in the movie time-line when you're pleased. All you need after this is to save your new movie file.