CrispSofties (http://www.crispsofties.com/) has updated its iPod.iTunes music synchronization tool to version 4.5.3, which has been tweaked for iTunes 9.2.1.
iPod.iTunes does real add-synchronization, even in two directions if desired. The source can be either the iPod or the iTunes library. The software evaluates the source for songs, videos, podcasts and/or playlists that are not in the target and only adds these seamlessly, avoiding duplicates. Unlike iTunes’ own synchronization iPod.iTunes generally does not delete content in the target. iPod.iTunes can also transfer song dependent data like “My Rating”, “Last Played”, “Play Count”, album artwork, etc.
iPod.iTunes can be used for: keeping files and playlists on different Macs and iPods up to date; doing a full restore of songs, videos and playlists from iPod; reversing the accidental deletion of songs, videos and/or playlists in iTunes, if these are still on your iPod; transferring an iTunes library from one Mac to another via the iPod; synchronizing to a “foreign” iPod (not linked/synced to your iTunes library) without deleting content on it or touching the link to it’s home Mac; synchronizing to a linked/synced iPod without deleting content on it; “cloning” an iPod; and backing up and iPod.
iPod.iTunes is Universal Binary so runs natively on both PowerPC and Intel Macs. It requires Mac OS X 10.3.9 or higher and iTunes 4.2 or later.
iPod.iTunes costs US$39.95. Version 4.5.3 is a free update for registered users of version 4.x.