(Image from Endgadget)
So there we have it. Finally the incessant rumours can end. Others can post the specific specs and stuff if they want, but the basics are right there in the picture. Not seen is the back, which is indeed a touchpad.
Here are some videos that I stole from another forum.
Games overview
Hot Shots Golf
Uncharted
Little Deviants had a pretty neat application of the rear touchpad, like my beloved Marble Madness or Kororinpa games.
More details on the system's media and functions are on the first link I posted from Endgadget, where they would have more details that would just be better read there or other tech/gaming sites.
No indication of the price. I wouldn't be surprised if it costed as much as a PS3.