Wiimmfi definitely is, although I'm not sure if animal crossing works on it. (I vaguely remember both DS and Wii versions have support form wiimmfi)Is this still up and running ? I recently started playing my DS again and was saddened to find out I couldn't use the multiplayer function/visit other animal crossing towns anymore. There are certain upgrades you can only get by having a friend visit.
Also, if you need a town to visit, I have mine here, although I haven't really touched the game since... last year... lol. XD
On top of that, time to dig out my WEP-enabled D-Link... XD