The first steps into the realm of Nintendo Network.
http://www.nintendoworldreport.com/news/31930
A listing at retailer Walmart indicates that North American players can expect rebranded Nintendo eShop cards in the near future. This was uncovered by gaming blog Trendy Gamers.
The new prepaid cards will allow you to purchase content (described as "games, videos and more" on the package) on the Nintendo 3DS as well as the upcoming Wii U console, which will be launching on November 18. There will be three different variations to choose from: $20, $35 and $50. The cards can't be used on the Nintendo DSi Shop or the Wii Shop Channel.
At this point in time, no information is known about when the cards will be available. However, it is to be expected that these will pop up on or near the Wii U launch date.