Unless it's a specially formatted song, a piece of music is just a series of wavelengths. It depends on the song what wavelength the "voice" will be at; for example, a piece by Andrea Bocelli would have vocals at a "lower" wavelength than an Enya song would. Stripping away vocals from a piece of music is very difficult, because sometimes the vocal range mixes with other ranges -beats, synths, etc-...
Just my two cents. I use the music programs "Sound Studio" and "Ableton Live" for my editing. I'm not personally aware of a program that does exactly what you're looking for.