I can't seem to find the answer I'm looking for in any of the threads, but I recently moved to an area that has very bad cellular coverage. We are in a basement, and the only place I get service is if I leave my cell phone on a window sill. Since I have wifi, I should be able to use iMessage to send and receive texts without service, correct? meaning 0 bars, no service (as opposed to no data service) And is it just limited to iPhones or can it be any phone?