Well I am with At&t right now. I want to buy a Iphone off Ebay. I just got a Blackberry about 4 months ago and I have no upgrades. I have the Data service plan so I can get email's and go on the internet via my Blackberry. Will this same plan work with my new Iphone in which i will be buying tomorrow. I just want to make sure I can send txt messages and stuff on the Iphone. I can at least do that right?