Use your PC's internet on your Windows Phone thru USB cable
I found this by accident and have written an article over it:
Basically Windows Phone has this built in functionality of allowing u to use the internet connection of your PC when its connected via USB. You don't have to do any set up at all. There are a few requirements though:
- You must have a Windows Phone with WP 7.5.
- When you connect your phone to USB, you must keep Zune running in order to use internet.
Using Laptop / Computer Internet on Windows Phone (via techomaniac)
Thats it! Enjoy my dear WP users. :)