I have recently installed MeBoy emulator on my blackberry curve (can't be bothered to say the no.) and according the the website ( http://arktos.se/meboy/ ) it could play sound from version 2.2 I think. I went to options -> Enable sound, then I saved my options.
I was trying to get sound on Pokemon Crystal and Super Mario Bros. Deluxe, but no sound was coming out at all. My bb's sound was turned on, settings were normal. I even increased the volume to max so I could try and hear something, but there is still no sound.