2 Words: Action Replay
you run around sinnoh and it will hatch.
run around
Yes
Have the egg in your party and walk around lots. To make the egg hatch quicker, have it next to a Pokemon with the flame body or magma armour ability.
You have to walk around with it. It will hatch faster if you have a Pokemon with the ability Flame Body.
have a magmar or magmotar in your team next to the egg
you can't hatch a pikachu egg on diamond, it hatches in to a pichu.
you walk around for ages and ages and it will eventually hatch
You have to have the egg with you and walk several thousand steps.
Have a Pokemon with the ability Flame Body or Magma Armor
I don't think there is!
It depends on the Pokemon you are hatching.