I've updated the game. Now in version beta 6 it have sound (it is very low, but it's there) and music support. Please test and tell me if you have problems.
To install, just place the Apps folder in your root and then open the /Apps/Rockbot/Rockbot_NDS.nds.
Rockbot 0.1 beta 6.zip Source : forum.gbadev.org
Site Officiel : rockbot.upperland.net