Although Animal Crossing was released in the USA in September 2002, the European version (PAL version) was put on hold until Nintendo could see how the game would perform in North America. Nintendo reasoned that AC was a new genre of game and were hesitant to spend time and money to release a game that might very well bomb around the world. The company chose to release the game in America as a test to see how audiences responded to it. If the American release was successful, then they planned to convert the game to the PAL format for European and Australian audiences.

But then something happened. Animal Crossing because a smash hit in the USA and development on the sequel was fast-tracked. In January 2003 Nintendo concluded that by the time they localized and converted the first AC game for the PAL market, the sequel would be ready for release. Therefore Nintendo decided to not release Animal Crossing in Europe, causing the game to join the ranks of other games released worldwide but not in Europe (such as Super Mario RPG). By extension this means that the Animal Crossing e-reader cards will also not be released in these regions (provided the e-reader is ever released in those regions).

On the other hand, don't cry too hard for Europe. While the USA was turning Animal Crossing into a smash hit, Europe was exclusively enjoying another new genre game: Doshin the Giant.

Japan, meanwhile, gets all the cool stuff. In June 2003 Nintendo announced plans to bring the American version of Animal Crossing to Japan so that our friends across the Pacific Ocean can enjoy some extra features and bonuses that weren't in the original version released there. Some of these extras are exclusive to the Japanese re-release and are marked in the list of additions below with an asterisk.

  • Upgraded animal designs *
  • Conversations and topics are changed *
  • All-new events added *
  • More than 100 additional items *
  • Visit the island without a Game Boy Advance *
  • Receive items using passwords
  • Save village data on SD Cards (using the SD Memory Card adapter) *
  • Take photos of village life, store on SD Cards, and print using photo printers, etc. *
  • Transfer data to the game using the e-Reader
  • Get letters from animals and import designs via cards
  • Link up to the Game Boy Advance and play all-new mini-games *
  • Download NES games to the Game Boy Advance via the link cable.

Nintendo has no plans to release the upgraded version, known as Doubutsu no Mori e+, outside of Japan and is instead focusing development energies on the upcoming Animal Crossing 2.


References:
http://www.n-philes.com
Japanese re-release specifics from http://pocket.ign.com/articles/424/424524p1.html