I've had problems getting my Palm m105 to Synch in OS X since the OS X version of the Palm software came out.
Have a look in your Login Items (SystemPreferences.app) to see if there is more than one of
each of the following:
- Palm Desktop Background
- Transport Monitor
Both of those items should be there, but no more than once. If you only have one of each, try unplugging your USB cradle and plugging it back in. For some reason OS X loses the connection to the cradle.