Ive been doing some searching and came across these 3 sites
linux-bcom4301 sourceforge page
linux broadcom 4300 linux driver
bcm43xx specs page
for those of you wanting airport extreme drivers these are all worth a close look at. Wish I was more comfortable w/ programming or Id either use the specs and roll my own (shouldnt be really any diff then programming my picmicro controllers-minus adding the kernel api) hope this helps some of you out there