Broadcom hardware
The ["../../users/Drivers/bcm43xx" bcm43xx driver] was written based on the specification at http://bcm-specs.sipsolutions.net/ and http://bcm-v4.sipsolutions.net/.
Airgo hardware
An ongoing project is at http://airgo.wdwconsulting.net/mymoin/
Atheros hardware
http://openhal.org/ has just started.