Yeah, that's something I would be interested it.  I had some, but none worked correctly, because some instruments will hit the same range as vocals.  IT worked to a certain point, but also drowned out some of the music.  I never found one that works, and I don't think it exists where it completely removes vocals, while keeping the music 100% in tact.  If this software existed, there would be REAL Karaoke music out there instead of the reproductions done in studios...

Yeah it is a rap song mainly that I want to remove the vocals for and use the tune as my ringtone, the only thing is this is a remix and I only want to get rid of the rap part.

Thanks for the help anyway.

Here's a youtube link, I want the backing tune and lyrics just not when the guy voice.
http://www.youtube.com/watch?v=Fg8hZUVDUHw