Here are some details -
"The Nine Inch Nails edition of Tap Tap Revenge will go on sale in October and will have 16 specially selected tracks from Nine Inch Nails’ most recent albums, The Slip and Ghosts I-IV, many of them specially edited or mixed for the game. And it will of course have that special NIN look and feel. As far as we know, this is the first significant music partnership of its kind for the iPhone! The game will retail for $4.99."
*WHOA EDIT* Check this out - http://www.nin.com/pub/taptap/
"nine inch nails is currently developing its own iPhone application, scheduled for release before the end of the year. watch nin.com for details."
Another app? Interesting.