N73 does not have the hardware to connect to wifi but still u can
1. Buy a bluetooth dongle.
2. Connect the bluetooth dongle to your laptop and enable bluetooth in N73.
3. Get internet in N73 through laptop.
(More info : http://web.singnet.com.sg/~kinston/Bluetooth%20Internet.htm
U will not be able to connect to public wifis only to ur laptop...