Most audio editing softwares can do that, but the quality after
vocal removal varies with the song you use. 100% of the time, the
overall quality of the song drops, the only question is how far it
drops.
Google Search for Vocal Remover
I'll recommend you to find a KTV VCD of it and rip out the
audio.
I have a website for Chinese KTV mp3s only. PM if you want the
URL