By far my favorite tuner App, now for a buck.
“For a limited time, we have reduced our price on iStroboSoft to 99 cents! No promotion code needed. Visit the App Store to purchase.
Peterson Strobe Tuners popular StroboSoft tuning application for the iPod touch and iPhone. iStroboSoft™ offers the unmatched accuracy of a mechanical strobe tuner for the highest degree of precision available in a software tuning application.
Plug in and tune your electrics and acoustics quickly and easily with 1/10th cent accuracy. (External mic required for iPod touch.)
Peterson Tuners has offered tuning solutions for over 60 years and is the only company specializing in hardware and software tuning products for all levels of musicians.”