Nintendo does these sessions with Satoru Iwata about the Wii U
hardware every once in a while. Well, he just finished one up talking about the hardware inside the Wii U itself
A panel of four people from the R&D department sat down with the President of Nintendo to discuss the inner workings of the upcoming console. They don't go into real specifics, but do get into some detail like how the CPU and GPU are on one chip now, which is what the AMD's Fusion lines of APUs are.
The fans and the heatsink have increased in sized from the Wii, due to the more powerful hardware that's present in the Wii U.
There's pictures of a clear Wii U console, which Iwata is excited about and I agree with him that it should be sold. It's kinda cool looking and certainly more exciting than plain white in my opinion. There's also tiny little details like the Wii U's cover for the front USB connectors and SD card slot now opens without sticking out of the front like the Wii.
It's a nice quick little read into the design of the Wii U. Chuck, Jeremy, and Sean Colleli went and saw the console up close a few days ago so be sure to check out their impressions when they post them.