Basically you will require a NLE package that supports multiple overlay tracks. You will need to use Picture in Picture to achieve the effect.
The principles of what you want to achieve are more adequately described in this post,
However, your moving paths will be much more complex.
COMPAQ something or other with 500Gb Boot Disk, 1Tb external Firewire Disk, 4Gb Memory and a super duper sound card, 19" TFT Monitor etc etc etc
Sony TRV33e : Sony TRV310e : Canon XM2
Sony Vegas Studio editions to v11
Remember, there is always more to learn than there is to teach.