The tattler currently uses a GSM/GPRS/UMTS modem. So the carriers are ATT and T-Mobile. I chose T-mobile because they have a $15/mo unlimited SMS text message pay-as-you-go plan. So for $15 a month I can get unlimited messages for the tattler. AFAIK there is no better deal. I have at least one Qualcomm based UMTS modem working with the tattler, so I should be able to get a Verizon (all Qualcomm based) one to work. But my first attempt failed with the Novatel USB760 on Verizon because the Novatel doesn't support an AT interface for sending SMS text messages. If you have a recommendation for a Verizon modem (that I can pick up cheap on eBay) I will give it a try. I'm currently stuck with ATT on my iPhone until the 5 comes out in October. Then I will switch back to Verizon. I hate ATT (and I would still hate them even if I didn't work for QCOM)