Fender Tune
It's not the first guitar tuning app. It's just the first from a company that actually makes guitars. Fender Tune is designed to let everyone from the beginner to the touring musician get the most of their guitar. It uses the company's proven DSP technology to ensure tuning accuracy, and adaptive feedback to help you along. There's also a section of tone tips that can help you get your amp and guitar sounding their best, a section of tips for beginners, and a variety of pre-set tuning options, with the ability to save your own custom tunings and upload them to Fender Connect for access across all your devices.