How fast does it need to be?
Most cellphones on the market now have data link cables that let you hook them up to a laptop for dialup connections. As long as you can dial out on your cellphone, and you have a dialup account, you're good to go.
Some cellular providers are rolling out enhanced data services (3G and a few others whose acronyms I forget) that are significantly faster than 14kbs, but they are very new and quite limited in access areas at the moment.