Gsm Sim Card Reader Can I Buy An AT&T GoPhone And Put My Current AT&T GSM SIM Card In It, And Will It Work With My Contract?

Can I buy an AT&T goPhone and put my current AT&T GSM SIM card in it, and will it work with my contract? - gsm sim card reader

I am currently under contract with AT & T and a GSM phone with a SIM card. I need a new phone, but not much and I am not a new contract. Can I have a GoPhone from AT & T and put my SIM card into the computer and work?