If you have a devalpha and if you love karaoke, please have a look at my app : FSL mobile - BlackBerry App World
As it is a new app, I'm waiting for usability feedback (what works for me doesn't necessarily works for you), and ideas.
It only works with "cdg" files now, but I will add AVI very soon and I'm currently writting all the stuff needed for "kar" and "mid" playback.
Thanks to all those that will try it.
A port for Playbook will be done ASAP, as it will probably be my main target.
I can provide a bar if needed.