You are going to need some specifics around your request. What do you mean by tethering device? What exactly are you trying to do.
Tethering normally means using a cell phone to connect a PC to the internet for data. Not the other way around.
If you want to enable internet connection sharing (ICS) then yes, you can:http://www.maximumpc.com/article/howtos/howto_turn_your_windows_7_pc_wireless_access_point