Can you use a smartphone with at&t prepaid?

Okay, so I know that with at&t, they use simcards [chips] with their service. and I used to have prepaid through at&t, and i would just take my chip out, and stick it in any phone and it would work. But if i tried to put my chip into a smart phone, say a blackberry or something like that, would the internet and everything still work? or would i have to buy a data plan? and can you even buy a data plan with prepaid?

Before swap your sim card,You must consider the following details.
1.Check your sim whether it's properly fit on your Blackberry phone or not.
2.You should have data plan on your AT&T prepaid sim.
3.Your Blackberry phone should be unlocked one.If it's locked to other than AT&T means,you will need to unlock your phone.For unlocking visit UnBBLock.com Here you can unlock your phone at low cost.