Here's a simple guitar tuner that supports multiple tunings. This is a universal app for both iPhone and iPad. Some of us guitarists prefer to tune by ear. This app plays the notes of popular guitar tunings.
Features: Beautiful graphics with high resolution retina display support; fantastic string vibration animation; hear sine tones or a sampled clean electric guitar; hold mode plays one note at a time indefinitely while you tune; free mode behaves like an actual guitar. Great for listening to how the strings sound together in each tuning; auto mode cycles through the strings automatically for hands-free operation; currently, 6 tunings are supported.