I have just added karaoke (only .cdg) functionality to my jukebox called JavaTunes. If anybody is interested please help me test it. When MP3 or Ogg files with a matching .cdg files is added a new Karaoke tab will be visible. The jukebox needs Java 1.3+

http://stigc.dk/projects/JavaTunes/

Use the link with the text "JavaTunes karaoke"