My sister is on my family plan and has a blackberry which is breaking down.  She does not have any data plan on her phone.  We have the family plan's unlimited texting package.  I have an iphone 3G 16GB and my contract is going to expire.  I wanted to give her my old iphone and just upgrade to a new one.  My question is will AT&T still force her to get a data plan if she plugs in her SIM card and even if she turns off the roaming and 3G network etc?  Is there any way for us to get around her having to get a data plan also? 

Any info would be greatly appreciated.

The 30 dollars on a family plan is for unlimited texting. However, you can get a 15 dollar data plan . She could get a iphone 3 for 49 dollars and her line charge would be 9.99 a month. I was told that I would have to have their SIM card but they could transfer my contacts from my old SIM card over to my new IPhone .  For those of you that are not aware of it. AT&T has added a free service but you have to ask for it. Your mobile to mobile ,use to be only to other AT&T customers. Now , Mobile to Mobile is to any other cell phone carrier. Your minutes are from land lines only,but you need to request that they change you to their new plan. It is free and they do not charge for changing you over.