I just restored my iPhone 3G (fw 2.1) I am using Universal SIM Unlock
So I inserted my SIM card and went to Mail, Contacts under settings, and tapped on Import SIM Contacts. A little message popped up for an instance, "Importing Contacts". Then I went to my Contacts, and there was nothing.
I tried turning the phone off and on again twice, but I faced the same problem.