In the olden days, when you bought a MobileMe subscription and told iCal to sync with MobileMe, the events in your calendars located in iCal’s on my Mac collection would sync with MobileMe. However, Apple changed how MobileMe calendars worked and provided an upgrade process to move those synced On My Mac calendars to a new MobileMe collection in iCal. You’ve probably already received email from Apple explaining how to upgrade your iCal calendars.
That upgrade process, however, works only for those who have previously synced their On My Mac calendars with MobileMe. If you use iCal and have never synced your On My Mac calendars with MobileMe calendar if you want to sync it with MobileMe, here’s how you do that:
1. In iCal, select a calendar in the On My Mac collection of calendars and then choose File> Export> Export.
2. In the window that appears, give the exported calendar a name, and choose where to save it(temporarily) on your Mac.
3. In iCal, choose File > New Calendar and then choose your MobileMe account from the new Calendar submenu. A new, untitled calendar appears in the MobileMe collection in iCal’s sidebar.
4. Rename the untitled calendar. You can use the name you used for the On My Max calendar that you exported, and then click Import.
5. In the Add Events window that appears, choose the new MobileMe calendar from the pop-up menu, and click OK.
When you complete that last step, iCal imports the calendar into your new MobileMe calendar. In the future, any events you add to this calendar automatically sync with MobileMe. In the future, any events you add to this calendar automatically sync with MobileMe. If you like, you can delete the calendar that you exported from your Mac and deselect the old On My Mac version of the calendar in iCal’s sidebar.