1UP reports that Capcom is releasing a portion of Ghost Trick: Phantom Detective to the iPhone App Store in Japan. The initial download will be free, containing two chapters of the formerly DS-exclusive puzzle adventure. Additional chapters will be available for ¥600 ($7) each, or ¥1,500 ($18) as a bundle. The DS version was released in Japan in June, six months before the announcement of this iPhone port.
Capcom has yet to announce this for the West, and likely won't until after the January 11 release of the DS version. Another well-known game by creator Shu Takumi, Phoenix Wright: Ace Attorney, has also been ported to the iPhone.