I'd like to chime in to the OP when it comes to rooting. If you decide to get the OTA 2.2, then you will not be able to root until a root method has been released for the OTA which as of right now is not the case.
PDANet does work, though can't speak as to whether it works on OTA 2.2. PDANet does however work through USB and not WIFI.
My recommendation is that if you want to have a wireless tether, you root now while you still can, do all the updates on the radio yourself, grab a 2.2 ROM and wait for the OTA to be released by one of the Custom ROM devs and in mean time you can have WIFI Tether and will eventually have it on the OTA, and even better, the OTA without all the extra bloatware.