Install ipw3945-source, ipw3945d, and firmware-ipw3945 using APT:
# apt-get install ipw3945-source ipw3945d firmware-ipw3945
You will need to make sure that you have module-assistant installed. If not just use APT:
# apt-get install module-assistant
Next use m-a to compile ipw3945-source:
# m-a a-i ipw3945-source
Edit '/etc/network/interfaces' using a text editor and append the following lines of text to the end:
# The wireless network interface
allow-hotplug eth2
iface eth2 inet dhcp
