You can find it here: http://sourceforge.net/projects/canta/
It uses the win32ada binding to access all the Windows functions.
It is a real-time software without tasking, it just uses the hardware
interrupts generated by the audio card. It implements a simple FFT to
analyse the voice pitch. The graphical interface is home made. Several
skins are available. The user interface could be in French or in
English, other languages are easy to add.