The latest version of Mass Storage Synchronizer — the add-on from Tea Vui Huang that adapts iTunes for Sony Ericsson, Nokia and Samsung phones — is now compatible with Palm One's Treo 600 and 650 smartphones. You'll need RealPlayer for Palm or Pocket Tunes to hear the music. It will be interesting to see how the 650 handles music storage given its non-volatile memory problems. Anyone with a Treo 650 out there want to download MSS 1.3 for us and report back?
Mass Storage Synchronizer [Product Page]