I use Salmon King's. My jukebox skin in mamewah has a single item in the list "launch the jukebox", which launches SK.
Maybe it's not what you want to do though.
I have been toying with the idea of having the jukebox play at the same time as mamewah and the games, so that you can go in the jukebox app, build a play list, then switch to mamewah and start maming while your songs are playing.
Not sure how to do this though.