From January 30th, 2011 to February 5th, 2011, players of Pokémon Diamond, Pearl, Platinum, HeartGold, and SoulSilver Versions can get Ash's Pikachu which is seen in the Pokémon TV show and movies. A DS Download station will be setup at participating Toys 'R' Us locations.

The Toy's 'R US press release specifically indicates that the content distribution is not offered at competing retailers in the USA in 2010.

Ash's Pikachu should be identical to Satoshi's Pikachu which was distributed in Japan earlier this year. It knows the following moves: Volt Tackle, Iron Tail, Quick Attack & Thunderbolt.

Source: http://www.toysrus.com/shop/index.jsp?categoryId=4311963