You and I are in the same boat here. Weather is knocking our internet on and off and I need it for weather warnings. To get tethering to work on GB flash the tether hack from TBH (the one he took down). Then install "Wireless Tether" from market. Fire up wireless tether and set up your SSID and stuff. Then turn it on. Stock tethering will pop up saying you are tethering (thats fine) go to stock (via notification bar) and set up tethering there with the same exact settings as Wireless Tether. Then turn on and off wireless tether (stock one) and then click off "mobile network" if that option is available (sometimes it doesn't pop up)... then go back to Wireless Tether, turn it on and off and then back on. Boom, tethering works.
I know this is convoluted, but it does work. I did it last night during the storms. I don't support free tethering, but if its the safety of my family or using a few mb of data to find out the weather... I'll use the damn data.