A question about unlocking a 3650 Nokia phone.

I had my Nokia 3650 unlocked using the code given to me by somebody from this forum/site. (Though, I haven't tried it yet with other service provider, but I did get the "sim restriction off" message.) And now I'm thinking of giving my phone to my cousin (in the Philippines). I was just wondering if she would be able to use the phone using a sim card from the Philippines without any problem. Or do certain things need to be changed or added (e.g downloading softwares for the phone)?
I was reading some of the messages here... and I kinda have a notion (base from what I have read) that one can use an unlocked phone(triband) to any country that supports the said frequency by simply using a sim card (service provider).
So, could somebody please clarify this for me. Thanks in advance.

... don't know if this would matter - I bought the phone here in New Jersey (USA) and originally with aT-Mobile service. Thanks again.

yes fone will work anywhere only thing that you will have to configer is the browser settings