I dont know how get the action replay for the system then put in the shiny pichu code
Yes it can, but where is Shiny Pichu anyway?
no
yes they're the same game
No, that is only avilable for Pokemon HeartGold and SoulSilver. But a Shiny Pichu can be obtained in any game with Pichu in it, but it's really hard to find.
you keep catching pichu until you get one or you use action replay
No, infact the game has a pervention method to pervent a Shiny Notched Ear Pichu from being shiny.
you must try trading pokemon from d/p/pt
The chances of finding a shiny Pokemon is normally 1 in 8192. That's a 0.0122% chance of finding one! Or you can do it by this Idea: Ask you're friends for cheating a shiny pichu and trade it. if you got shiny pichu you can get a Spiky-Eared-Nitched Pichu.
Only by trading with someone who already has it.
No, not anymore. They are done with doing events for Pokemon HeartGold and SoulSilver.
Yes, you need a special event Shiny Pikachu that was given away by Nintendo earlier in the year in order to get the event for the Spiky-eared Pichu to be unlocked in Pokémon HeartGold.
The Pikachu colored Pichu, a.k.a the Shiny Pichu, is only obtained through events, unless you are lucky enough to hatch one thru an egg