I did this with my rooted 2.1 phone, but my non-rooted 2.2 phone does not have the wireless hotspot option. It will do USB tethering.
It appears to me that to accomplish wireless tethering with 2.2 you need to have your phone rooted and install a wireless tethering app.
If you only need to have one computer use the tether, you can use the USB tether. Go to Settings, Wireless and you should see a USB tether option.