With this new Kin Media Sync for Mac application you can sync your iTunes music, photos, and movies between your Kin and Mac computer. You simply fill out the registration form with your name and email address to get a free registration code. Mark/Space is well known for creating sync clients for the Mac so it makes sense that Microsoft used a known entity to help in this area and the tool looks quite capable.
As a Zune HD and Mac owner, my first thought was that this tool could be used to sync up my Zune in some way, but unfortunately this does not work so don't worry about trying it out.