Continuing with the joy that is Ubuntu 11.10 Oneiric Ocelot and how it completely messed up my previously working wireless, here’s a solution. Note that I’m currently using a Dell Core i3 Inspiron using the following Broadcom network adapter:
Broadcom Corporation BCM43224 802.11a/b/g/n [14e4:4353]
You can run lspci -nvn | grep -i net from a shell console if you want to find out which card your machine uses.
Anyway, long story short, you may need to remove the wrong drivers and install the correct ones. This solution worked but may not work for everyone depending on your hardware:
Remove and uninstall the drivers:
sudo apt-get purge broadcom-sta-common broadcom-sta-source bcmwl-kernel-source
Install the correct one:
sudo apt-get install b43-fwcutter firmware-b43-installer
Enjoy and let us know if this solution worked for you. Found a different solution? Tell us about it!
edit: This solution still seems to be working up to current version of Ubuntu 14.10 aka Utopic Unicorn