I've had lots of experience with Intel drivers. If you have a latest Debian version, the drivers should be included with the kernel automatically. All that will be required is the microcode, which you might find in Debian's repositories, or, if not, here:
If your Debian distro is up to date, it's not recommended to change or install a new ieee80211 subsystem.
So, in short, skip the ieee80211 install, and grab the microcode either from a Debian package, or from the website.
If the wireless driver is not automatically initiated, try "modprobe ipw3945"
If you get an error, go ahead and install your kernel sources and kernel header files, and install the Intel driver from here:
Hope this helps,
The regulatory program ipw3945d may be useful to you afterwards. See if you can install it from Debian's packages.