Useful App for Guitarist
I wanted to recommend an app that I have been using a lot for my lesson and my personal practice its called GuitarToolkit - Agile Partners . Here's a description from the company's web site.
GuitarToolkit is a collection of essential guitar tools for your iPhone, iPad and iPod touch. An extremely accurate tuner, a precision metronome, more than two million chords, scales and arpeggios -- GuitarToolkit has it all and tons more. It’s so good, Apple inducted GuitarToolkit in the App Store Hall of Fame.
For theory students, the chords, scales and arpeggio resource is great. As you learn a new chord you can look up how you can hold that chord all across the fretboard. If you want to play the G major scale, you can see all possible positions of the G major scale (or any other scale).
If you're in my one of my Music Theory Workshops, bring it with you.
Very useful app, worth the money.