I remember I had a Winamp plugin once that can remove voice during play back. However, because with mp3s (or even the wav file created from CD), the voice is mixed with the music during the production of the audio tracks. Once it is mixed together, it is very difficult to extract just an individual piece (such as voice) out from the final track. The plugin I had only did simple calculations and removed sounds that are equal on both left & right channels. Of course, if some music are also mixed equally on both channels, they would also be removed and it would sound hollow-ish as if nothing is playing.
 
I do not think there is an existing free (or cheap enough to buy) program that can do full voice removal. A skilled sound technician with million dollar sound equipments may be able to do manual adjustments and tweaking to get a seamingly perfect voice removed track. But for an average joe, I don't think there is anyway to truely do voice removal from a song

It is highly unlikely unless you have all the individual tracks. It's like trying to take out Darth Vader from the finished star wars films....

I'm not really bothered if ALL the vocals are taken out, as long as they are not overpowering, so that karaoke-ing can be done over it. There must be something out there that can erase some vocals... doesn't have to be THAT professional!
 
EuriMouse