At&t SIM going from 3GS to ip4

[lurch0101]

I'm giving my iphone 4 to a family member who has been using an iphone 3gs for a while (both of us are on the same fam plan). If I walk into an AT&T store, will they give me a micro sim and activate it on the iphone 4 ?

I would also like to give that same 3gs to another fam member from the same family plan who has been using a motorola v551. is this possible without adding a data plan?

 

[Mike J]

If you throw a sim card with no data plan on it into an iPhone, they will add a data plan. Even if you don't ask them to, they'll detect it.