Studying in California this semestre and is going back to Denmark at Christmas.

When I came here in august I paid a $500 deposit, got my iPhone 3g wondermachine and have been paying my contract ~$70 a month.

I have been told by customer care, to change my adress before I leaves to my Danish adress, so they can send me a check with the deposit to that adress. Since AT&T does not provide services in Denmark I don't have to pay the $175 for early termination.

That was the situation description now the question.
I want to buy as many iPhones as possible... Do anybody in here now if it is possible to add 1,2,3 or more lines to my account, and then close them, when I get out of the country.

Can I do it without paying more deposit?

I doubt they will give you the phones without more of a deposit. They already didn't trust you enough to give you one without a deposit why would they be willing to give you many without any more money?

If they did give them to you then you can close them and not pay ETF. It says in the contract if you move where they don't have service they will let you out of the contract without the ETF.