If your smartphone has usb tethering support then all you need is the appropriate usb cable and you're good to go.
If your pc already has a wifi interface card or dongle you can already use that to connect to your smartphone if you enable your phone as a wifi internet hotspot. No need to buy anything else.
I don't have any wifi hardware other than my cdrk 5354U router/wifi. I have thought about tethering through usb but I don't feel comfortable with hot usb port. But after reading your reply, it just occurred to me that the wifi dongle will still use usb. So I guess I might just go with this.
I planned on using a wifi dongle that's why I'm asking for a suggested hardware. But on second thought, they also use usb. So I might just use my S3's tethering feature.