im sorry >> not sure if against rules but ill state this
easist way to rip GBA music and sounds:
simple Download VirtualBoy EMULATOR. and some games you want (if you already have them of course). then play the game and kill out Music channel or SFX channel and then hit the sound record on the EMU and it will save as a .WAV and you can edit with some sort of program. Simple as that.
Edited your post to "fit" the rules.