The Tether app works but it still isn't 100%.
Mine won't shut down until I force close it. If you don't encrypt access, you should turn the phone off and back on again when done, because force closing doesn't kill tether access.
When the phone battery saving sleep mode kicks in, the tether is terminated until you wake it. I just occasionally tap the screen and that fixes it.
I don't use it a lot, but it has come in handy a couple times when I needed access on the fly or didn't want to make certain communications on my monitored work computer.
I am curious now with this new tether tracking rumor with Gingerbread.