the Lumia 900 has to be unlocked, which can be done with AT&T over a phone call for free, or go to a AT&T store and they'll do it for you. Or you can do it yourself if you wanna take the time.
Tablet? I'm looking for a service-that's free, where I can port my existing cell phone number to the app so I can text from my Nexus 7 as well as my phone, that way, if I don't have too, I can just take my Nexus 7 to places instead of my phone and my Nexus, yes I do realize I need an active...