[Flibmeister]

I know nothing about "real" tethering, but I'm using wmwifirouter on my Alltel Diamond. There are free older versions of the software floating around, but I don't mind paying for a good app, and this one is, so I was happy to pay the less than $30 it costs to register the current version.

Easy install, and it works great. The other day we woke up to find our DSL line down, so I fired up the Diamond and the wifirouter software, and we were using two laptops and an iTouch on it, all at the same time, for a couple of hours.

Best I can tell so far, Alltel doesn't know I'm using it, so there are no additional charges beyond my normal plan. Two downsides though: one, the phone runs hot already, and the app makes it run even hotter. Two, it eats batteries-- if I'm going to use if for any length of time, I plug the phone into the cigarette lighter or an AC outlet.