According to the Yomiuri, Nintendo have announced that they plan to release the successor to the Gamecube exactly a year from now, in May 2005. [edit: apparently they are going to announce the successor in May next year, which makes more sense]

There doesn't appear to be much more info than that, but it looks like they are jumping the gun on both Sony and Microsoft.

Then again, Nintendo are famous for not hitting their release dates for new hardware, maybe this date is also a bit pie in the sky.