Can you put a ATT prepaid sim card into an iPhone?

I still want to keep my prepaid service but I want a cool phone. So i want to get an iPhone. So if i put my sim card in the iPhone will it work? Cus I know the iPhone has free wifi so i could use it at my house without paying a 30 dollar internet plan. SO will it work?
Thanks alot to anybody that can help!!!!(:

Yes, provided the iPhone should not be locked with any other network. If it is, I suggest you can approach Classicunlocking.com and specify the country,locked network of iPhone.Based on the availability you can get the permanent unlock service along with free instructions.