Suggest using the search function for this forum and doing a search for vocal remover. I think that you will find that most plugin do not do very well and it is a very hit or miss proposition at best. The vocal has to be in the center and you will also loose whatever else in center panned so be ready for some not too good results. Even the best hardware or software solutions can only do so much and you will not be able to completely remove the vocal and it will still be there in any reverb or room amblience so it will sound like a backing vocal. It would be better to go back and re record or re mix the tune.

buy a karaoke machine at wal-mart and you're all set

$ .02

tom gave it to you straight...they dont generall work very well.... however if you insist what i would do is copy it into your puter...take one channel... (roll the dice for which) then reverse phase (flip/invert) one channel and bring them back together.... anything in both channels should diminish (read not removed) along with as tom told you anything else that was centered in the mix.... (typically bass/kick) or you could try recording something originall instead of useing MC DU JOURE' (f**k spyll chuckir)