I'm looking for a video editing program that will allow me to combine multiple videos/sounds into one screen. I already have audacity to combine the music if I would be able to just sync that with the videos separately, but I would prefer a program that could combine both video an audio. It'd be nice if I could find a free program that does this obviously. Here is an example of the type of video I want to make:

http://youtu.be/0InfkJ2gYXw