ANAHEIM -- At the NAMM Show last week, I got to see an amazing iOS app in action: GuitarToolkit ($9.99, iTunes) by Agile Partners. I originally discovered GuitarToolkit while searching for an app to tune my ukuleles and decided on the one that Apple had selected it for its App Store Hall of Fame. It's also the most highly-rated guitar tool on the App Store with mostly five star ratings.
GuitarToolkit is easily worth the $10 just for the tuner, which is amazing. It supports 6-, 7- and 12-string guitar, 4-, 5- and 6-string bass, banjo, mandolin, and ukulele, each with standard and alternate tunings. In addition to its amazing tuner GuitarToolkit also includes a precision metronome and over two million chords, scales and arpeggios.
If you're more than a casual musician you'll want to buck up for GuitarToolkit+. This $4.99 in-app upgrade gives you access to additional features, including: chord sheets that you can touch to hear and email to bandmates and students, custom instruments that allow you to select strings, pickups and even the texture of your fretboard, and an advanced metronome with up to 32 instrument tracks and 75 sounds.
Good stuff (and one of CNET's Top 5 iPhone guitar tools.)
Agile's other axe apps are pretty epic too. TabToolkit ($3.99) is a powerful tab and music notation viewer with multi-track audio playback and AmpKit+ ($19.99) turns your iPad or iPhone into a guitar amp and effects studio.