vfat is the device driver to support both FAT16 and FAT32 filesystems.
The most likely problem is that your mount-point is wrong; many such devices only use one partition, in which case it would be /dev/sdb1 not sdb2. Also, sdb is the second SCSI (or USB mass storage) device; make sure you have the right one.
The fact that you use the word “unrecognizable” implies that you are seeing files and directories with strange names (unusual characters). In which case, you have the wrong codepage selected; you'll probably want something like UTF8 or Unicode (at a guess).
You can change this in the options column of the fstab entry; A list of options for vfat can be found in the file /usr/src/linux/Documentation/filesystems/vfat.h
/dev/sdb2 /mnt/mp3 vfat noauto,users,utf8=true 0 0