I'm a total noob...just built a system running Mythbuntu 12.04 with an old Buffalo WLI2-PCI-G54S wireless card. Its the Broadcomm 4306 rev 3 chipset. I tried to use the b43 firmware and didn't get it working, so then I tried the ndiswrapper method. I learned that ndiswrapper won't work on my 64-bit architecture, because Buffalo's Windows 98/XP/2000 drivers are 32-bit. I was unsuccessful in my attempt to use some Vista 64-bit drivers.
To undo my ndiswrapper attempt, I removed the ndiswrapper packages I'd installed, and removed b43, b43legacy, and ssb from blacklist.conf.
I then installed b43-fwcutter and firmware-b43-installer. My wireless card showed UNCLAIMED using lshw -C network. Using "sudo modprobe b43", my wireless card was recognized, and the GUI network settings allowed me to find and connect to my network with WPA2/AES and a hidden SSID. An additional driver was NOT loaded. I made the fix permanent by adding b43 to /etc/modules.
CONCLUSION: I *think* the following (from a clean install) would have made everything work without the 10 hours of pain I invested:
If it works at this point, then type
sudo apt-get install b43-fwcutter firmware-b43-installer
sudo modprobe b43
This forum was instrumental in my education...hopefully this helps someone else.
echo "b43" >> /etc/modules