I think I can answer all the questions regarding unlocking the phone!

AT&T immediately provides the Unlock code for all the phones other than iPhone and Nokia. They never provide unlock code for iPhone. For Nokia, they have to request to manufacture so; it might take about a week for you to receive the code to your email address through Manufacturer.

You always have to tell them the reason as traveling abroad. If you tell you going to use for other carriers they might not provide you ever.

If you have already cancelled the AT&T service, it like impossible to get. However, have your friend who still has AT&T call cust service ask for Subsidy Unlock Code. The reason, once again, has to be the same. Hope this helps all the questions!

Cheers'