The Missing Sync for Palm OS 6.0.2 b4 is available as a free download from the Mark/Space website. Since this is a pre-release build of the Missing Sync, you should take the time to back up your personal data before installing the latest update. Feedback should be left in the Mark/Space forums as there is no other support options for the beta software.
I'm glad to see the new beta of The Missing Sync out so soon. Mark/Space is expecting to have a final release of The Missing Sync out 90-days after the October 26 release of Mac OS X 10.5 Leopard.