My cell phone died and I need a new one. So I was thinking of buying one from www.Amazon.com and I am not exactly sure of the exact criteria I need. My current cell phone service is through AT&T. I don't want to change service providers just my phone. Just curious can't I just take my SIM card out of my current phone and install it into my new phone I buy. I know if I buy it online it won't be discounted because of the contract commitment. I don't mind paying retail price for a phone. I just need to know like what criteria or suggestions I need to make a cell phone purchase. So if you can explain the unlocked vs. Locked phone be greatly appreciated. If you have any other information I need to know before when considering of buying a phone please let me know. Thanks!