Gamefly has added Wii and DS listings for The Sims 2: Castaway Stories to its website. There's no official confirmation of the title yet from EA, who have only announced it for PC so far. As the title suggests, the game will offer a story mode featuring 'romance and dramatic twists.'
These games could work really well on DS and Wii, particularly if the online/wi-fi aspect is exploited - imagine being able to create and share your avatars - or replays of your characters' most entertaining moments.
Castaway Stories hits the PC in Winter, with DS and Wii versions hopefully arriving shortly after.