It won't make much of a difference to the end user -- all they'll care is that they're getting unlimited voice and data for under $70 a month -- but it turns out that Zer01 Mobile's upcoming VoIP-based service won't be using AT&T alone to provide service. Instead, it'll have service agreements in place with a number of GSM carriers -- nationals and regionals alike, we'd imagine -- in an effort to keep its costs low. Because all voice calls will travel over VoIP instead of GSM or UMTS proper, it seems like things could get a little dicey if you find yourself on a crappy EDGE (or worse yet, GPRS) connection, but hey, just keep telling yourself: "$69.95."