I don't think there IS a spiky-eared (aka notched-ear) Pikachu. If you mean PICHU, the pre-evolution, there's a possibility to get him in Pokemon HeartGold or SoulSilver.
To do so:
You have to first obtain the Pikachu-colored Pichu. To do this, you can bring your Nintendo DS and a copy of Pokemon Diamond, Pearl, or Platinum into a participating Gamestop, and get your very own Pikachu-colored, "shiny" Pichu. Then, transfer that Pichu into your Pokemon HeartGold/SoulSilver game. The only way to get the Notched-ear Pichu is to join an event on Wi-Fi. I think, during this event, you take it to Ilex Forest. There's a shrine there; be sure to put the Pichu as your first Pokemon in the party before going to the shrine.
Hope that helps!
To do so:
You have to first obtain the Pikachu-colored Pichu. To do this, you can bring your Nintendo DS and a copy of Pokemon Diamond, Pearl, or Platinum into a participating Gamestop, and get your very own Pikachu-colored, "shiny" Pichu. Then, transfer that Pichu into your Pokemon HeartGold/SoulSilver game. The only way to get the Notched-ear Pichu is to join an event on Wi-Fi. I think, during this event, you take it to Ilex Forest. There's a shrine there; be sure to put the Pichu as your first Pokemon in the party before going to the shrine.
Hope that helps!