How do you unlock my old alltel phone?

Here's the unlocking instruction for Samsung A177 phone:

Switch ON your phone without SIM Card.

Compose: #7465625*638*CODE# (or *#7465625*638*CODE#).

Device should say: Network Lock Deactivated

There is other way to unlock any iphone, including samsung - factory unlock - http://digitalunlocking.com/ . Good luck !