Havak
I'm the Best. You're a Towel.
From Friday 5th March you'll be able to download the special Pikachu Coloured Pichu via Wi-Fi Connection. You'll have until Friday 26th March to download it for your copy of Pokémon Diamond, Pearl or Platinum. The Pichu is a Shiny Pichu and enables you to get the Spiky-eared Pichu in Pokémon HeartGold/SoulSilver which is also released on 26 March. As ever, you can download this Pokémon via Mystery Gift.
I'm not sure if this will work with US copies of the game(s), just in case anyone in America missed it, but I guess it's worth trying if you want it - although it's not exactly the most useful thing.