I'm starting to learn about wireless pentesting with BackTrack, and while learning how to find out the hidden SSID I wondered how could I connect to the wireless network after I discover the SSID. The book I'm studying does not cover that topic, only how to find the SSID.
ifconfig wlan0 192.168.0.1 netmask 255.255.255.0 up
iwconfig wlan0 essid "XXXX" channel X
but that doesn't work. Result in screenshot: