You have to talk to the Move Tutor for Piloswine to relearn it. An alternative is to breed a Swinub with Ancientpower as an egg move or to take it to a Move Tutor.
Make it learn AncientPower and then level it up.
to evolve piloswine, you have to have a heart scale and go to the move house in mistralton city, give her a heart scale and make piloswine learn ancient power and level him up once. if you don't want to do this you can get one in the giant chasm in rustling grass, but it has about a 10% chance of you encountering it.
You have to have a piloswine and have it learn ancient power. It learns ancient power at level 33, which is when it evolves, so you will need a heart scale abd go to Pastoria city and have your piloswine learn ancient power. Then just grow it a level.
You must use a Heart Scale at the Move Relearner's house for it to learn Anceint Power, its a starting level move.
Some Pokemon learn ancient power as they level up.
The Move Tutor teaches it to Pillowswine at any level, in exchange for a Heart Scale.
You must teach it via Heart Scale with Move Tutor in Pastoria City.
If its a tangela, then it will learn it at just below level 40 (I'm not sure when). Otherwise, take whatever Pokemon needs to learn it to the move tutor house in blackthorn city, talk to the fat guy in the pink and give him a heart scale. He will re-teach ancient power to your Pokemon, as nearly all Pokemon that need ancient power knew it before somehow :S to get a heart scale, smash rocks or buy them from the pokeathlon dome
Heart scales should work
its a move your Pokemon might learn
disc
Make it learn Ancient Power