iwconfig

Make sure wireless-tools is installed and then edit /etc/network/interfacese

12345678910auto eth1 iface eth1 inet dhcp wpa-driver wext wpa-ssid [ssid here] wpa-ap-scan 1 wpa-proto WPA wpa-pairwise TKIP wpa-group TKIP wpa-key-mgmt WPA-PSK wpa-psk [result of wpa_passphrase essid phrase]

#or

1234auto eth1 iface eth1 inet dhcp wireless-essid [ssid here] wireless-key [network key]

And to improve your wireless performance if you’re getting dropped packets use

1iwconfig [interface] rate 5.5M auto