This program functions similar to the typical guitar tuners you buy in stores, and anyone familiar with these shouldn’t need to read these instructions. Basically, you play a single string on the guitar, and the program listens to the note and tells you if the note is sharp, flat, or just right.

Funiculus can only be run on an iPhone (and not an iPod Touch) because the iTouch lacks an internal microphone.

http://sourceforge.net/projects/funiculus/