Will Korean phone be used in USA?

[ada09]

A friend of mine is travelling in South Korea. I want her to buy me a Samsung cellphone there. My problem is whether I could use it in USA with Carrier like AT&T.

[dontaskwhy]

Just make sure that the phone has both the 850 and 1900 mhz frequencies to operate optimally on the At&t network. Apart from that, the only other requirement is that the phone uses GSM and has a SIM card slot.