FretBoard

FretBoard is a reference tool – running on Apples iPhone^TM and iPod Touch® – for players of the stringed instruments supporting Guitar, Banjo, Bouzouki, Bass (4, 5 and 6 string), Dobro, Charango, Lap Steel and Pedal Steel, Mandolin, Violin, Viola, Cello, Lute, Viola da gamba, Ukulele, Dulcimer, all Chapman Sticks, all guitars and bass guitars tuned and set up for two-handed tapping, alternative guitar tunings and many other instruments. Currently FretBoard holds a collection of more than 140 instrument tunings in 15 instrument groups. FretBoard has an immense amount of music theory packed in a simple and intuitive interface guaranteeing fast access and easy understanding.

You will find more information about FretBoard on http://fretboard.mennigmann.com/