It's really easy, all you do is use the quick select tool and click on the white spots or where ever you need. It's one of the most useful tools in Photoshop IMO.
He doesn't give it out because people are like "OMG PLZ LEMME BE MOD I HELPED OUT AT THIS FREE FORUM AND SHIT SITE AT FREEWEBZ N IM RLY GOOD @ WUT I DO."