Nintendo's newest add-on for the Game Boy Advance1, the e-reader is a system within a system. It was released in Japan in early 2002, and is just now hitting U.S. game shelves in late September 2002. It is being promoted alongside the game Animal Crossing, currently the only Nintendo GameCube title to interface with the e-reader.
The e-reader is a barcode scanner which reads special barcodes printed on the sides of ordinary trading cards. These cards are sold in foil packs and may contain entire games, game data, or any other information that can be imported into a game. This effectively bridges the gap between the Pokémon video game (soon to arrive on the GBA) and the popular Pokemon Trading Card Game. Recent expansion sets of the card game have included e-reader-compatible cards which can be used to unlock features in the video game. Note that the e-reader cannot read standard UPC bar codes.
The U.S. version of the e-reader retails for $39.99, and includes two packs of cards: one contains a Nintendo Game and Watch mini-game, three Pokémon Expedition character cards, and an Animal Crossing interface card. The second pack contains either the NES classics Pinball or Donkey Kong Jr. You can choose which NES pack-in you want at the time of purchase: it is indicated on the packaging.
To load a game, insert the e-reader into the cartridge slot, power on, and swipe away. The NES games require multiple strips, as each strip encodes roughly 2.2 KB of data on the long edge and 1.1 KB of data on the short edge of a card. Instructions may be printed on the cards and/or the wrapper in which they come. Additional NES games (Excitebike-e, Tennis-e, Balloon Fight-e, Donkey Kong-e, Ice Climber-e, and Urban Champion-e, for starters) cost $4.99. Some of these can also be unlocked in Animal Crossing, which costs $49.99 by itself.
Information acquired from: http://www.nintendo-e-reader.com, http://pocket.ign.com, http://www.ebgames.com
1 Servo5678 tells me that the e-reader will also work with the smaller Game Boy Advance SP.