The vision of me receiving my phone bill and running to the nearest bankruptcy lawyer once I saw the total had me frightened, so I called Sprint.
Some very nice gentlemen told me in his best indian accent (sounded so authentic too!) that since I have unlimited data plan and free roaming, that I can absolutely tether my blackberry to my laptop at no addt'l charges to me.
I guess the real test will be when the bill comes. I do not plan on using it very much anyways (have comcast broadband @ home) but when I do go away it sure is nice to be able to connect!