Japanese shopping mall Ario Kameari (Ario 亀有) is offering a Nintendo Zone download station for Mew and Pikachu November 21st to November 23. Players of Pocket Monsters Diamond, Pearl or Platinum can receive the Pikachu while only players of Pocket Monsters HeartGold and SoulSilver can receive the Mew. Those that arrive early can also receive large stickers while supplies last.

Below is the information from the Nintendo Zone Pikachu.
Level: 40
OT： Ario (アリオ)
IDNo.： 11219
Ribbons: None
Moves: Present (プレゼント), Quick Attack (でんこうせっか), ThunderShock (でんきショック), Tail Whip (しっぽをふる)

Wonder Card Info: Pikachu that learnt 'Present' 「プレゼント」をおぼえた　ピカチュウ
Recieve the Pikachu that knows the move 'Present' from the distributor in the Friendly Shop. Take good care of it! After receiving it in the Friendly Shop, make sure to write your Report! (フレンドリィショップ　に　いる はいたついん　から　うけとってね わざ「プレゼント」を　おぼえた ピカチュウだよ。だいじにそだててね! フレンドリィショップで　うけとったら かならず　レポートを　かこう!)

Source: http://www.itoyokado.co.jp/special/ario234/pc/index.html & http://www.pokemon.co.jp/info/091116_01.html