Raspberry Pi Forums

You have to create that file: /etc/wpa_supplicant.conf
Above file must contain below code:
network={
ssid="WIRELESSNETWORKNAME"
psk="WIRELESSPASSWORD"
}

How to create the file and put that text?
vi /etc/wpa_supplicant.conf
Then start to text mode by pushing "i". Then type the context. To save & exit : go to command mode by pushing "ESC". Then type ":x"

You have to inform about above job. Edit /etc/rc.conf (vi /etc/rc.conf)
Add the below code at a empty line:
ifconfig_urtwn0=dhcp
dhcpcd=YES
dhcpcd_flags="-q -b"
wpa_supplicant=YES
wpa_supplicant_flags="-B -i urtwn0 -c /etc/wpa_supplicant.conf"

FINALLY reboot the system by "reboot" or "shutdown -r now".