I have been having issues with the BCM4322 wireless card on my macbook pro under ubuntu. As it turns out after some digging the BCM4322 driver only supports the ‘Rest of World’ locale which does not include wireless channels 12 & 13. You can test this by trying:

sudo iwlist eth2 channel

Which on the macbook pro returns: eth2 20 channels in total; available frequencies : Channel 01 : 2.412 GHz Channel 02 : 2.417 GHz Channel 03 : 2.422 GHz Channel 04 : 2.427 GHz Channel 05 : 2.432 GHz Channel 06 : 2.437 GHz Channel 07 : 2.442 GHz Channel 08 : 2.447 GHz Channel 09 : 2.452 GHz Channel 10 : 2.457 GHz Channel 11 : 2.462 GHz Channel 36 : 5.18 GHz Channel 40 : 5.2 GHz Channel 44 : 5.22 GHz Channel 48 : 5.24 GHz Channel 149 : 5.745 GHz Channel 153 : 5.765 GHz Channel 157 : 5.785 GHz Channel 161 : 5.805 GHz Channel 165 : 5.825 GHz Current Channel:1

As you can see, no channels 12 & 13. Since my router had been set to 13 (it was less popular in my area) this resulted in no wireless for ubuntu. After a quick change to the channel setting on the router, ubuntu can see my wireless network. To find a channel which is not too crowded try using nm-tool or perhaps:

sudo iwlist eth2 scan | grep Channel