Wii U announced at E3

Nintendo has announced the Wii U.

What we know thus far:

The new console is larger, bigger than a wii, closer in size to the slim Xbox360. 
The Wii U can output standard def or high def graphics that should be similar in quality to the PS3 and Xbox 360. The processor is supplied by IBM. The console has internal flash memory and support for SD Cards, no internal hard drive.

The big news is the controller.  It's a small slate/tablet style device with a 6.2" touch screen in the center and conventional controls around the edge, including the analog circle pads from the 3DS.  It has front and rear facing cameras, and motion controls via a gyroscope and accelerometer.

The controller can be used as a display for games in lieu of a TV as long as you are in range of the WiiU console.  The controller display can be used for innovative game modes.  Demos have shown a 2nd player flying a spaceship entirely from the controller using motion controls and analog pads, while the other players use the current Wii remotes and a splitscreen TV mode to try to shoot down the ship.  Other games use the secondary display as a inventory screen, a hidden playbook, a map, a rearview camera, and so on.

Specs are available here.
Pictures of various play styles here.