ipw3945d and therefore iwl3945d is not used anymore. I have the same wifi card in my Lenovo. With the new driver the card registers as wlan0.
You also need to have the latest firmware. Look in /lib/firmware and see if the file iwlwifi-3945-1.ucode is there. If
it isn't, google for it and you will be able to get it from Intel. Things should start working then.
Edit:
That pup is harder to find than I remembered. Get the file here...
http://www.intellinuxwireless.org/?n=downloads&f=ucodes_3945get version iwlwifi-3945-ucode-15.28.1.8.tgz