that's great news about PdaNet still working. I'm pretty disappointed about the built in tethering not working though. I tried both PdaNet and the tethering hack when I got my 3GS, and I felt like the built in tethering was more stable than PdaNet. I don't think it was just an Apple Placebo either.
In any case, if my iPhone gets screwed up and I have to restore, at least I can live with the comfort knowing that I do have an option if I have to move up to 3.1.