The standard computer form of the CD+G disk track is MP3+G (though there are also some proprietary formats I would doubt anyone is sharing), which is actually two files: a standard .mp3 and a like-maned .cdg with the graphics part.
Most MP3+G files are ZIPped together, not RARed, as there are karaoke tools that will work with the ZIPs directly (without having to unZIP them), but not so with RARs.
