Here's the best way to use lighting for filming yourself talking to a camera.

Lighting Techniques
http://www.lightsandcameras.com/waay_basic.php

3 point lighting
http://www.youtube.com/watch?v=AcMX1RcNRYA&feature=related

Also this explains where the lights should go
http://www.mediacollege.com/lighting/three-point/

Here's a professional DVD you can buy on it. The free video on this page is excellent to watch.
http://www.lightsandcameras.com/products.php