The following article is from Apple's website titled "Syncing iPhone and iPod touch with your computer".

URL: http://docs.info.apple.com/article.html?artnum=305741\\^{Image Modified}

Syncing iPhone and iPod touch with your computer

When you connect iPhone or iPod touch to your computer, items are automatically synced between the two according to your preferences. You can, for example, enter phone numbers and addresses of friends and family members on your computer, connect iPhone or iPod touch to sync, then unplug iPhone or iPod touch and tap a friend's name on the touch screen to call.

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