Can an unlocked Sony Ericsson K800i be used on the at&t network?

My home phone is set up on the at&t network and I just bought a Sony Ericsson K800i on ebay. Can I add this phone to my existing at&t plan? Are there any fees I will encounter?

Hello. If your Sony Ericsson K800i has been unlocked, you can definitely use any GSM network with it. Including AT&T network. If it has been restricted to some specific network, you need to unlock the device in prior. You can unlock your Sony Ericsson K800i safer and easier using unlock code. You can get the unique unlock code for a Sony Ericsson K800i from hSimpleUnlocking.com at affordable cost with an easy unlocking guide. Good luck.