If the player is UMS (mass storage), check the output of dmesg after you plug it in to your system. For example, my iAudio player is given /dev node sda.
I then use
Code:
mount -t auto /dev/sda /mnt/usb
to mount the drive, and move audio to it as if it were a regular drive. AFAIK most players that are UMS can be mounted as 'vfat' filesystem.
As far as management goes, I'm not to "up" on what's new and fresh, but I believe AmaroK has support for UMS audio players.