I don't think such software exists; at least not in the way I think you want.
If you have a sound format that supports many channels/tracks you can do it by using just the vocal tracks or just the instrumental tracks. WAV and MP3 formats -- and anything you'll get by ripping a CD, for example -- will be two channel (left + right) in one track. You can't split this easily. The problem is a lot of the frequencies used by the human voice are shared with the musical instruments. If you attempt to remove one of them you risk "damage" to the other.
Some programs (Cool Edit Pro comes to mind) offer a "vocal removal" feature for stereo tracks. However, they fudge it by masking the left channel with the right channel (invert one and add it to the other to produce one channel). The result is a mono track with all the sound common to both tracks removed. This works in some cases to remove vocals because they are positioned in the centre -- same sound on both tracks -- where as the instruments are spaced out.