The Apple iPhone offers users a number of tools and options for making the process of transferring phone numbers and other contact information from an old phone or contact manager simpler. Whether you use a contact manager such as Address Book, Outlook Contacts or Google Contacts or you are trying to move your contact information from an old phone onto your iPhone, the process is simple and quick using either iTunes or the iPhone's "Import from SIM" command.
Connect your iPhone to your computer using the USB cord and launch iTunes.
Select your phone from the "Devices" section of the left column in the iTunes application window. Select the "Info" tab at the top of the window.
Check the "Sync Contacts" box and check the boxes of the services you want to transfer numbers from. Select "Apply" in the bottom right corner of the application window. The contact information will sync to your iPhone.
Remove the SIM card from your old phone and place it in the SIM card slot of the iPhone. The iPhone SIM card slot is at the top of the phone. You can access it by sticking a pin or other thin object through the hole at its left.
Select "Settings > Mail, Contacts, Calendars > Import SIM Contacts" on your iPhone.
Take out your old phone's SIM card and replace it with the iPhone's original SIM card. The phone numbers and contact information from your old phone will now be in the "Contacts" application in your iPhone.