A couple of months back I posted a message about a new karaoke website I had found which you could use with students ( http://www.redkaraoke.com/ )
Since that time I've found two more and each one is better than the last.
http://beta.luckyvoice.com/ This site is still under development, but has some marvelous features and a really good collection of songs and play lists. I've written a complete review of the site at: http://quickshout.blogspot.com/2008/08/great-new-karaoke-site.html
But the best one so far forr me is http://www.karaokeparty.com/en mainly because many of the songs also include videos of the original singer with the lyrics. Students who register can also get a score on their singing ability, which may also help to motivate them to repeat the song aand do better. You can see a complete review with screen shots at:http://quickshout.blogspot.com/2008/08/another-great-new-karaoke-site.html
Lastly, if you want to read my tips and ideasa for teaching with karaoke go over to my learning technology blog at:
Happy singing, and if you do have any of your own ideas for using karaoke with EFL studentss please leave me a comment below.