Broadcom BCM43xx Wireless Cards
Overview
Broadcom BCM43xx series wireless cards have opensource drivers for ubuntu but the firmware required isn't installed by default. For these cards to work they need a package installed and the firmware extracted.
Ubuntu 12.04
Sometimes when Ubuntu is upgraded to 12.04, the broadcom drivers are blacklisted, resulting in no wireless or wired if either are broadcom. Follow the directions here to troubleshoot this issue. Note that at least Broadcom 4306 requires firmware-b43legacy-installer instead of the firmware-b43-installer.
Ubuntu 10.04
Lucid has finally included both the open b43 and b43-legacy drivers, as well as Broadcom's proprietary driver in its repositories. If you have a BCM43XX, it's now just a matter of going to System >> Administration >> Hardware Drivers and letting Ubuntu work its magic. Make sure you're connected to the internet (and clicked through our wireless splash page) before attempting it!
Ubuntu 8.04 Hardy Heron and before
These distributions are no longer supported.