This video will show you how to get Mamoswine in your Pokemon Heart Gold and Soul Silver game.
After you have evolved your Swinub into Piloswine, take it to Blackthorn City and go see the Move Tutor (move relearner?). Teach it Ancient Power, and hand over the Heart Scale. Then, just level it up one level, while it knows Ancient Power, and it will evolve into a Mamoswine!
How to Catch Swinub:
Thanks for watching; be sure to check out my channel for more Pokemon videos!