Chiff and Fipple Forums

Does anyone know of an app where I can combine 2 separate videos into one concurrent split screen video? I thought it'd be fun to record myself playing a tune, then record myself accompanying that tune, and merge them into one split screen video. From reading up on it, I think that iMovie might do this, but I'm not certain. Or if it's my best option even if it does do this.

Basically this, but I don't plan on being as flashy or have as many screens going on.
http://m.youtube.com/watch?v=qAWKllY697A