I remember trying to get Ubuntu to work on my Compaq nx6125 my freshman year of college. The first and biggest hurdle was getting the wireless card to work. Recently, after a few OS changes, I decided to go back to Ubuntu for that machine. Imagine my dismay when I discovered the documentation on the process hadn’t changed much since my freshman year! Fortunately with a little digging I was able to find a much simpler process. If you’re trying to get your Broadcom card to work in Ubuntu 11.10 (and possibly earlier versions, for all I know), simply run:
sudo apt-get install firmware-b43-installer
And that’s it. Your wireless card should work.
Edit: If you’re not using Ubuntu and want to get your Broadcom 43xx wireless card to work in your particular flavor of Linux, you can find more documentation on the subject on this particular page of the Linux Wireless website. That’s where I discovered that handy little bit of command-line wizardry.