Scanning for wifi networks :
ifconfig wlan0 up scan

Setting up your wifi device :Network-Wireless

This example shows the Atheros ath0 wireless adapter.Add an entry for this network to /etc/wpa_supplicant.conf. If the file does not exist, create it. Replace myssidand mypsk with the SSID and PSK provided by the network administrator.

network={

ssid=”myssid” psk=”mypsk”

}

Add entries to /etc/rc.conf to configure the network on startup:

wlans_ath0=”wlan0″
ifconfig_wlan0=”WPA SYNCDHCP”

Restart the computer, or restart the network service to connect to the network:
# service netif restart
After 8.0v, it is necessary to create a wlan clone device of the actual wifi card :
# ifconfig wlan0 create wlandev ath0
# ifconfig wlan0 up list scan