After the guys from SDL-Wii fixed the sound initialization code, sound is working better than ever (well, it's working for the first time).
To commemorate this event, I've uploaded a new version of BennuGD-WII code-named "Comes With Music". Basically, what this is is a version of Bennu that integrates the functionality found in mod_sound (minus a few bits related to the definition of these globals that I'll hopefully add sooner than later).
The code uploaded comes with a module tracker example song that will play when you unpack the contents of the archive to the APPS folder of your SD card and load it through the Homebrew Channel on your Wii, but the binary should allow playback of many other song formats: OGG, WAV, MP3, MIDI...
Hope you like it!