The Missing Sync for Palm OS makes it easy to synchronize with Mac OS X apps like Address Book, iCal and Microsoft Entourage, eliminating the need for Palm Desktop and HotSync Manager. Supports many Palm Powered handhelds, including those from palmOne, Sony, Tapwave, Samsung, Garmin and AlphaSmart. Connect over USB, Bluetooth or even Wi-Fi.

PocketMac GoBetween is a plug-in for the iSync program built into the Mac OS.  Allows you to sync PIM data such as Entourage contacts, calendars and tasks.  Syncs with iCal and the OS X Address Book.

Requires Mac OS 10.3 or higher, Microsoft Office X or 2004.