What do I need to connect my linux mini laptop to internet via a mobile carrier such as Sprint?

I will be traveling a bit in the next few months to homes and through airports without internet access. Running to wi-fi cafes would be quite inconvenient.

I need a primer on how to connect to internet via a mobile provider.

What equipment do I need?

What is the service call?

Cost?

We use spirint for our cell phones… Should I consider Verizon for this service?

Anything else I should know?

Does it matter what OS one has? I use Linux/Eeebuntu…

Many thanks!