Verification - Vista_Cupcake_Tetherbot works
Just posting to verify it does work although it took me hours of diddling...
Some observations augmenting the Tetherbot instructions...
Download and install the current Android SDK (1.5). Note that if you've been tethering using the USB driver from the earlier SDK, you may need to update the USB driver.
I <highly> recommend completely power cycling the G1 to clear out all the junk and make maximum resources available. Until I did that, I kept getting partial connections. Also power cycling while connected by USB seems to cause the USB driver to be re-recognized and probably update.
Note that the power cycling recommendation should address all the recent posts about unrecognized devices, blank/white pages loading without errors and more.
Install the Firefox FoxyProxy plugin. Add a new Socks 5 Proxy configuration for Localhost:1080 and to support DNS queries using the proxy.
Open only a maximum of maybe 3 instances of Firefox and maybe 5 total tabs. My initial trials seem to indicate that more connecctions might be overloading the poor phone's limited hardware.
Good luck everyone... Yes, it seems that running Tethrbot does not require root access and works fine with Cupcake (Android v1.5). And, this applies to Vista SP1, fully patched... No need to roll back patches as recommended earlier in this thread.