As a permanent attendant in the menu-bar, Tune
This Mac app helps you clean up your iTunes library.
Highly accurate professional guitar tuner with a very simple to use interface on your Mac.
Tune Backup provides a easy-to-use backup solution for your iTunes library.
Expands your iTunes application and boosts its functionality.
Auto-Tune 5 RTAS-The Next Generation Standard in Professional Pitch Correction.