i am transferring some shows to my nomad jb3 right now on a mac.
the driver works as an itunes plugin. it will recognize that the jb3 is plugged in to the usb, and you can transfer audio files back and forth, but only over usb1.0.
keep this in mind, the progress bar in itunes will not work correctly, but when the progress bar dissapears the track is transferred. took me a little to get used to that.
you can also change the startup screen with the itunes plugin. check the archive section somewhere under jb3 startup screens and there are a few there or you can make your own. i have the akg startup screen on my jb3
good luck