Comment 17 for bug 62452

I also got issues under feisty with my inspiron 945m from dell.

the kernel:
Linux mejai 2.6.20-6-generic #2 SMP Wed Jan 31 20:53:39 UTC 2007 i686 GNU/Linux

the card:
0c:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)

the issue:
while networkmanager can see wireless networks, it didn't manage to connect any, be it protected or not.

the solution:
$ wget http://bughost.org/ipw3945/ucode/ipw3945-ucode-1.14.2.tgz
$ tar xzvf ipw3945-ucode-1.14.2.tgz
$ sudo cp ipw3945.ucode /lib/firmware/2.6.20-6-generic/ipw3945.ucode

And everything worked just fine after reloading the kernel module.
Hope this helps