In a similar style to how 3DS was announced, and with rumours charging through the pipes of the Internet at a speed that would make Captain Falcon blush, Nintendo have put out a small press release confirming that a Wii successor does exist - and it's going to be present at E3 2011.
Masters of revealing as little information as possible, Nintendo coyly say absolutely nothing of its capabilities, only that it is due for release sometime in 2012, and that it will be shown in playable form at E3, being held this year June 7th - 9th, along with more specifications. Of course, this could mean that it's playable on-stage and not for general consumption, and "more specifications" could mean anything that Nintendo wants it to.
The full release can be found here.
How much do you think Nintendo will show at E3?