Ok you didn't mention WPA in your first post, linux supports WPA fine, after READING the Back Track forums (I dont use WPA) it looks like the wpa_supplicant has an issue with madwifi.
I'll try and help but cant guarantee it will work.
Download the wpa_supplicant module from Here
and the README from
Save both of these to a thumb drive and boot up Back Track.
Mount the thumb drive.
Now insert the module
all going well you now should have "/etc/wpa_supplicant.conf"
Edit this file to suit your needs.
With any luck that should be it.
wpa_supplicant -D madwifi -i ath0 -c /etc/wpa_supplicant.conf -B
The -B will let it run in the background. Then you issue:
to start the GUI interface so you can scan for APs and connect.
*** IMPORTANT ***
You must ALWAYS start wpa_supplicant FIRST before running wpa_gui!
Once connected you will have to manually do:
to get an IP address over dhcp.
All these steps worked for me except actually connecting as I dont use WPA.
Edit fixed URL's