This tip is from iPhone: The Missing Manual, Second Edition. Teeming with high-quality color graphics and filled with humor, tips, tricks, and surprises, iPhone: The Missing Manual quickly teaches you how to set up, accessorize, and troubleshoot your iPhone. Instead of fumbling around, take advantage of this device with the manual that should have been in the box.
Here's a pretty cool feature you may not even have known you had. It lets you route all calls made to your iPhone number to a different number. How is this useful? Let us count the ways:
When you're home. You can have your cellphone's calls ring your home number, so you can use any extension in the house, and so you don't miss any calls while the iPhone is turned off or charging.
When you send your iPhone to Apple for battery replacement (page 346), you can forward the calls you would have missed to your home or work phone number.
When you're overseas, you can forward the number to one of the Web- based services that answers your voicemail and sends it to you as an email attachment (like GrandCentral.com or CallWave.com).
When you're going to be in a place with little or no AT&T cell coverage (Alaska, say), you can have your calls forwarded to your hotel or a friend's cellphone. (Forwarded calls eat up your allotment of minutes, though.)
You have to turn on Call Forwarding while you're still in an area with AT&T coverage. Start at the Home screen. Tap Settings->Phone->Call Forwarding, turn Call Forwarding on, and then tap in the new phone number. That's all there is to it-your iPhone will no longer ring.
At least not until you turn the same switch off again.