First check you r4,does it already have moonshl,if yes,you can upload songs of mp3,ogg,nsf,gsm,mod,spc,mid format.If no, you can download it at
Http://files.cngba.com/Mr.T/moonshell15_with_dpgtools12.7z
and the upgrade software:
http://files.cngba.com/Mr.T/20061212_mshl15fdpg2beta2.rar