I am wondering what the final answer is on tethering to a laptop when you have a PDA data plan. I would like to get a phone or a PDA with a pda data plan, but would also like to be able to tether to my laptop for the occasional time I don't have internet access for the laptop. I realize they can not make a distinction but the tethering would be a backup approach and not a full time thing for the laptop.

What is the final say on this in terms of what plan and cost I would need?

Thanks,
Mark