Most Cell Phone providers have the option to do this. All you need is the data cable and be subscribed to sometimes one of their many Net Plans.
I have Nextel, and I've seen it done, hell we processed credit cards with it. It used a 14.4 or a 19.2 kps connection but it was a connection! Didnt pay a thing( other than the Net service, which comes included with some plans) either cause what it did is use your regular minutes, and if its a weekend and u have free nights and weekends...well then you get the point!
Kevin |