This shouldn't be a surprise to anyone for several reasons. First, 'Twilight Princess' was never meant to be a Wii game, therefore the first Wii Zelda game should be in development. Second, from the moment Nintendo decided to make the Wii they'd have been stupid not to have a team working on a 'Zelda' game for it. Third, it takes about three years to make a 'Zelda' game, so the timetable seems about right.
I love it when sites report on things they read in a magazine that are blatantly obvious to anyone with half a brain on their head. Granted, I'm doing it right now, but seriously, if there wasn't a Wii 'Zelda' game in deep development, now that would be news.
In other 'Zelda' news, 'Phantom Hourglass', the DS game with the cel-shaded stylings of 'Wind Waker' is reportedly being delayed until October of 2007.