Take a look: http://toucharcade.com/2010/01/15/taiko-no-tatsujin-rhythm-drumming-game-coming-to-iphone/ it should have been out since march. i want it now! And hey Konami, how about a Dance Dance Revolution update oder Pop n Music for iOS?
Taiko no Tasujin has been out in Japan for a while. It seems it isn't worth an international release, probably because of music liscensing.
Well if you don't wan't to keep waiting, if you have a DS order it theres only 2 of them at the moment for ds
They're releasing a bluetooth drum controller for this game. Pretty neat. 8700 yen comes out in December.