Hurray, iChess is now available on the iPhone/iPad!
Disclaimer: It does not have the usual flair of the Android version, but it will get there!
You can open your own tactics PGN file (by placing the PGN file in the iChess Documents folder via PC/Mac). However this option is available only for Paid users (iChess upgrade). You can grab one of the Promo codes below to upgrade iChess!PROMO CODES (Hurry before somebody else uses them!)4RW4NFXYHJX7YLT37W47HKLWWJ96A79NWM7TK6K446FAFH6EJFTLPXRWTE3A
Edit: It turns out that Promo codes cannot be used for In-App purchases, but only for Paid apps! (sigh)