Sync iCal and Google Calendar

Spanning Sync provides two-way synchronization between Google Calendar and Apple iCal., makes it possible to connect Google calendar to your iPod, and by syncing through Google Calendar, share calendars among multiple Macs. The latest release (1.2) adds faster syncs and inheritance of iCal default alarm for events synced from Google Calendar. It’s $65.00 (expensive) for Mac OS 10.4.8 and up.