How to set up reverse tethering over USB?

1. My HTC G2 phone is rooted and running Cyanogenmod 7 1. I don't have a data plan. 1. Sometimes I want to connect the phone to the Internet when there isn't Wi-Fi, to update Market apps, backup SMS messages to Gmail, sync new contacts from Gmail, etc. Things I can't do with USB mass storage mode. 1. I have a Windows 7 Professional computer connected to the Internet, but I'm not allowed to set up an ad-hoc Wi-Fi network. (If I do, they will notice and hunt me down.) Is there a way for the phone to access the Internet through the USB connection to the computer? If so, how do I set it up?