Karrde's right. I've tried effacing vocals from tunes, such as Modern Mouse's 'Float On', and Linkin Park's 'Numb'--The results were terrible to say the least. But if you're really gung ho about this then I suggest you try Audio4Fun's AV Music Morpher Gold 2.0.
EDIT: Gung ho? It would mean you're expressing 'much enthusiasm' for the music editing.