If you're using the Intel ipw3945 driver version 1.2.0 or below, this likely applies to you. I was running into a pretty serious issue with my laptop, where the ipw3945 driver (with version 2.6.23.1 of the Linux kernel) caused random kernel oopses every now and then. I was starting to suspect a hardware issue, but googling around revealed that this was actually a known bug in 1.2.0 (the version I had installed), and that it has been fixed since 1.2.1.
If you suspect you have this same problem, it can be fixed by installing v1.2.1 or newer.
James