Are you asking about wanting to get it unlocked to use in other countries? The iPhone 4 on Verizon can never be unlocked since it doesn't have a GSM radio in it. It doesn't have a SIM card slot either. Also even if the phone was physically capable of being unlocked you need to be a current customer of Verizon Wireless and the phone need to be on an active line along with other qualifications to be eligible for requesting an SIM unlock.
Thanks, Ann. I don't understand much about 'unlocking' phones. I am an existing Verizon customer, but am going to sell my iPhone 4 and wanted to make sure I didn't have to unlock it first. Your answer was very helpful.