Mobile internet in the US ?

[Catfish]

I am planning to go to Florida, buy a boat and do some sailing. In order to be able to go online, what would be the best solution for me ?
Is there a flat rate package for mobile internet like UMTS or GPRS or similar that is available without making a long-term (more than 6 months) contract ? Any suggestions welcome.

[AceHigh Pino]

I was under the impression you weren't required to have a contract to use PC connect cards for your laptop via Verizon, Cingular, etc?

[Catfish]

the question for me is, can I subscribe to one of those services for a limited period of time as a foreign national without US adress ? I'll check their websites.