USB tethering: share your Android phone’s mobile data connection with a single computer via a USB. (for device running Android 2.2 or higher)
*You can’t share your phone’s data connection and SD card via USB at the same time.
How to enable USB tethering:
1 - Connect your Android phone and computer using USB.
2 - Press Home , press Menu , and touch Settings to open the Settings application.
3 - Touch Wireless & networks > Tethering & portable hotspot.
4 - Check USB tethering.
The phone starts sharing its mobile network data connection with your computer, via USB connection. An ongoing notification is added to the Status bar and Notifications panel.
To stop sharing:
- Uncheck USB tethering to stop sharing your data connection. Or just disconnect the USB cable.
If your computer is running Windows 7 or a recent distribution of some flavors of Linux (such as Ubuntu), you typically don’t need to prepare your computer for tethering. But if you’re running an earlier version of Windows or another operating system, you may need to prepare your computer to establish a network connection via USB.
http://www.android.com/tether provides current information about the computer operating systems that support USB tethering.