There are countless apps for iPhone/iPad platforms, many geared towards guitar players, so it is sometimes hard to figure out which ones are worth it. I've tried a few, and the one that has been proven consistently useful is
Guitar toolkit, so I thought it'd be helpful to share a very brief review with others here.
This app provides the following features:
- A chromatc tuner
- A metronome, with various tick sounds and optional light flash synchronized with up/down beats
- An extensive library of chords, showing suggested fingering positions on a virtual fretboard that allows you to hear how the chord sounds
- An extensive library of scales, also laid out on the virtual fretboard
- A "chord finder" feature, where you select notes on the virtual fretboard and it tells you which chord the notes make
- Configurable tuning modes (EADGBE, drop D, CGCGCD, and many others): chords and scales automatically update with respect to tuning settings
- Configurable base pitch for the chromatic tuner: choose a pitch for A from the default 440Hz to many other lower/higher frequencies in steps of 0.5 Hz