Totally free guitar tuning software for Windows based computers.

This piece of software for the PC is more than just a chromatic tuner. It is an excellent way to teach intonation by recording and analyzing the wave forms of individual notes.   The program is written by a Japanese gentleman so parts of the program are in Japanese.  Still, it is a useful, functional program with fingering charts included for most common instruments.

The macintosh version of the Auto Tuner program, a full featured tuner and intonation trainer.