First of all, those of you who spent time with Animal Crossing: Wild World on the DS, you can transfer your avatar over to the new game. Another cool DS-to-Wii feature will allow you to "take your travel data and download it to your DS." We've no idea what that will entail exactly, but it sounds promising.
As for the Wii game, the holiday-themed events will be returning. Jingle the Reindeer will be back for Toy Day and a new character, Zipper T. Bunny, will make an appearance for Bunny Day. Sound promising!