I know to produce decent voice overs for audio files, you need to have an amplified microphone. Some people recommend buying a decent mic, and a preamp. Any reason why you couldn’t hook a karioke machine to the line in on the sound card and basically do the same thing. The wife has a decent karioke machine with a pretty good mic, but I haven’t ever tried to hook it up to pc and record audio… There must be some of you out there that have had the same crazy idea!
If the karaoke machine has a line-out (even a headphone jack will do) and the sound card a line-in there is no reason why it should not work. I suppose that if you look around hard enough, you will find a way to rip CD-G to WAV which would be a lot better way to go about it.