is it a usb drive? if it is, it should appear as hdx, where x is a letter like hda, hdb, etc. i think the difference between sda and hda is that sda is a scsi drive, but this isnt something i know that much about. but, you can try this: if it is a usb drive, plug it in, reboot, answer some possible questions (like what the device name is, fs type, options), then try this command:
mount /dev/your_external_drive_name /where/you/want/to/mount/it
ps: have you tried using a hardware mp3 player under linux? i was wondering how well they work...