Wireless Data

I would like laptop internet access,via cel, on my boat this summer. I bought a Motorola V551 (Cingular) anticipating high speed connection with bluetooth, then found they want to charge for minutes, data transferred and Media plan. I have ATT dial up service at home and have a 3-com cellular modem PC card (3CXM556) which I used with my Nokia 6150 (1500bps). I am aware of a Radio Shack cord with software. What is a good way to go to get dial up speed or better at a modest charge. What hardware and software is needed and where is it sold.