If you’re running MAC OS 10.6 Snow Leopard you can still sync iCal with your iCloud calendar by adding a CalDAV account in iCal preferences.
• Start iCal and open preferences ( ⌘, )
• Select the Accounts menu and click the add account ( + ) button
• Select CalDAV from Account type
• Enter your iCloud Username & Password
• Enter the following Server address: p06-caldav.icloud.com
Click Create to add your iCloud account and sync your calendar events.
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