An app to mute vocals

Does anyone know of an App that effectively mutes vocals from a song, I've tried vocalzap but was very dissappointed. Failing that, is there a Mac software that can do the same and then transfer to iTunes and then the iPod/iPhone?

Thanks
Grant

I've never seen anything that can do it effectively. The best workaround is getting the karaoke version of the song.

its is impossible to remove vocals from a stereo bounce of a song. the only way to "remove it" is by cancelling out the frequencies the vocal takes in the spectrum, which of course, it can share with other instruments. which means you wouldnt cancel that out too.

Karaoke here we come then, thanks guys