how to config wireless with iwconfig

1. list the wireless ap
iwlist scan
2. set the $ssid name of ap
iwconfig wlan0 essid $ssid
3. set the $key of wep
iwconfig wlan0 key s:$key --> ascii mod
iwconfig wlan0 key xxxx-xxxx-xx --> hex mod
4. specify the ap's mac
iwconfig wlan0 ap xx:xx:xx:xx:xx:xx

obtain ip address from:
dhclient wlan0