So I picked up 3M's headlight lens restoration kit the other day.
This guy:
All you need to use it is a 1200-1600 RPM drill/driver.
Before:

After:

The most dramatic results were when I used it on my fiancee's Grand Prix GT because her lenses were in rougher shape.
Before:

After:

I recommend this product, $29 CAD to make your headlights look 10 years newer.