The 'song' product we have on the CD is a mixed down version of perhaps 20-30 channels into a stereo (2-channel) mix. You cannot remove an individual vocals. It's sort of like asking can I remove the hi-hat cymbal from a finished song?
There are some EQ filters that can take out the frequencies of the human voice. I think this is what Cool Edit does. But you loose other parts of the song with that as well.
You can find karaoke versions of songs out there which are mixed from the record label without vocals. Try to find those, perhaps?