[pgfpro]

I manage a PPG, Dupont, BASF refinish paint store. We sell a few different headlight restore kits. IMHPO I think the 3M part#39008 kit is the best bang for the buck. It will only do two headlights that are extremely oxidized.
The 3M kit uses there 3M Trizact sanding paper that's a plus.

The main advantage the 3M has over other headlight restore kits is that you sand the old bad plastic off, then using the Trizact paper you take it to a final 3000 grit before you finish with their compound.

You can add a great final touch that will extend the life of your repair by using UPOL aerosol clear over the finished sanded compound product. It has UV screener in it to keep the headlights from yellowing later on in life.