How to hand-down your old iPhone after upgrading to iPhone 3G

Giving your old iPhone to a family member or friend

• You can hand down your old iPhone to someone else while activating your new iPhone 3G at an Apple or AT&T store, or anytime thereafter.
• Since your original iPhone's phone number is going to be used on your new iPhone 3G, the person receiving the original iPhone will need a new SIM card, which you can get by stopping by an AT&T retail store.
• You can add a new line or transfer an existing line to the original iPhone from home using iTunes. If you need help adding a new line, you can always walk into an AT&T store and see an associate.
• Once you've obtained a new SIM card for the original iPhone, the original iPhone can be activated through iTunes like you originally activated it.
• If the original iPhone is instead activated with its new SIM card in an AT&T store, you'll want to later connect it to iTunes and select "existing customer" to complete the process, even if you're new to AT&T.
• Users who'll be porting a non-AT&T phone number for use with an original iPhone can review the required number porting information covered in one of AT&T's earlier video guides.
• If AT&T tells you your out-of-area mobile number is ineligible for porting, try the steps taken by AppleInsider's Publisher last June when he successfully ported his 'ineligible' mobile number to AT&T and iPhone.

A video guide covering the hand-down process follows. AT&T is also offering a PDF file containing similar information and instructions on how to remove and replace an iPhone's SIM card.