iSync is a software application published by Apple Inc. It runs only under Mac OS X and is used to synchronize data in iCal and the Address Book with .Mac and with devices including iPods, many SyncML-compatible mobile phones and Palm OS handheld organizers & smartphones. PocketPCs and Windows Mobile devices cannot be used with iSync, but are supported by third-party applications. Prior to the release of Mac OS X v10.4, iSync could also synchronize a user's Safari bookmarks with the .Mac subscription service provided by Apple.
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I just love to have all my contact information synced with my Mac.
But: - missing photo, music and notes sync
Very good for syncing iCal to my Cellphone