I have an iMac G4 and two PowerBook G4s all running OS X 10.4.6.
iSync synchronizes my calendar between the 12" PowerBook and my iMac but not between the 15" PowerBook. (If it's relevant, the 15" PowerBook G4 was the most recently updated to 10.4.6 with iLife '06).
I have tried resetting the sync data on .Mac from each computer and then resyncing the other computers with that supposedly new sync data. This doesn't work regardless of order (i.e., reset with the 15" PowerBook and sync with the other computers, reset with the iMac and sync with the 15" PowerBook, etc.).
Because I carry the PowerBooks in different sites, the calendars are now hugely different. Any suggestions for how to get these in sync with each other??