Supported Broadcom Devices
Driver is available..
Is this for a laptop or a desktop ?
The Driver install is going vary for different distributions, so you need to choose one before you can get specific instructions.
the b43 (broadcom 43xx driver) is now included in the Kernel as of 2.6.24, I believe. but the firmware is proprietary and must be loaded manually since it is illegal to distribute with most Linux distributions.
b43 the Broadcom Linux Driver