After running 12.10 updates on my laptop with Broadcom 4312 wireless my wireless broke with the new 3.5.0-18 kernel update.
To fix I went into Software Sources & disabled the STA driver then I'm assuming at least the last 3 commands in this fixed it:
I didn't have to reboot or anything. It just immediately found my wireless adapter and connected wirelessly again.
sudo modprobe -r b43 ssb wl
sudo apt-get remove bcmwl-kernel-source
sudo apt-get install build-essential dkms linux-headers-generic
sudo apt-get install bcmwl-kernel-source