Is there a way to share my desktop Internet connection with my Android 2.2.1 using the phone data cable?
Well, it can be done with rooted 2.2+ devices. It's not simple.
Before I start, you might just find it easier to buy a cheap USB Wifi dongle and share the connection to your phone through that. It's a much more simple procedure and doesn't require root on the phone.
But here's how to do it over USB:
To reverse it all:
To make things slightly easier there are a few Apps out there that do the phone side of things (ASProxy for example) but you still need a rooted 2.2 device. The computer side of things can be scripted. You could even hook into udev to fire these commands off when you plug the phone in (and destroy the bridge when you unplug it).
There are some old notes on Reverse USB Tethering with Android 2.2 with a Nexus One.
I've been planning to try this without rooting my HTC DHD.
Requirements from those notes are,