The 6230 music player application on the phone will only play files in the "Music files" folder in flash ram, it will not play files from the memory card.
As you only have <8MB memory, that makes the 6230 a useless MP3 player.
Is there a firmware upgrade for this, or a way to change the folder where music player looks? I can't find it.
Moving files from memory card to Music files can sometimes fail, the file is not listed in Music files in Gallery but it can be played from Music player.
I have loaded many CDs worth of music to a 256Mb MMC card. It is best copied to the root folder on the 'B' drive. There have however been some problems with 'Phone Full' when over 50mb remains free and transfer is much slower than the drag and drop of my previous 3300.