Comment 23 for bug 732677

I have the same problem with bcmwl-kernel-source
03:00.0 Network controller [0280]: Broadcom Corporation BCM4311 802.11b/g WLAN [14e4:4311] (rev 01)
2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:50 UTC 2011 i686 athlon i386 GNU/Linux

I have read a workaround (that works in my case):
Remove the bcmwl-kernel-source thar comes with natty.
Install the bcmwl-kernel-source ( from maverick using gdebi
It can be downloaded here (i386):
or here (amd64):