This is my second iPad but my first one with cellular connectivity. I was wondering when I do add the service on it (AT&T), would it be separate from my phone account? Specifically, would it be an "extra", data only, line on my account or is it a completely new account? Thanks! I also want to add about switching SIM cards. My sister has the original iPad and I had the iPad 2 with just WiFi previously and now getting the new iPad. She doesn't do anything on it, maybe browse 2 days a week. The rest of the time the kids watch netflix on it. But when at home, it's always connected to the WiFi. What I'm asking is that would I be able switch our SIM cards between our 2 iPads without having to do anything to either of our accounts. Basically, can I just physically swap it between the two with no involved customer service and anything else?