If you have some contacts in your SIM card and you want to import into your iPhone 4 here is a quick guide to do that, follow the given steps to transfer SIM contacts to your iPhone 4. You can use this guide to import SIM contacts to iPhone 2G, 3G, 3GS and ofcourse on iPhone 4 as well.
Import contact from SIM card to iPhone 4
Insert your SIM card into your iPhone.
Tap on Settings icon on Home screen.
Tap “Mail, Contacts, Calender…” option.
Scroll down little bit, find “Import SIM contacts” button and tap on it.
Now open your contacts on iPhone and your will see all SIM contacts will be available on your iPhone.