Yesterday I got it working very well.
My puter is Acer Travelmate 2480
I installed 10.4.8 and then 10.4.9 update
Then remove the Extensions.mkext and .kextcache, make sure you repair permissions so they are correct.
(You can do that from the disk utility if you like.)
Open term and check if there is both AirPortAtheros.kext and AirPortAtheros5424.kext. If so remove the first one.
Happend to find out this is not actually needed, instead if this file is created simply go edit
0 on the first and 1 on the second. It seems like if any new kext runs after this these posted changes it adds the new kext and also add a new block instance in NetworkInterfaces.plist. Ask if I do not make any sense?!!??!?! :-P
then sudo nano /System/Library/Extensions/IO80211Family.kext/Contents/PlugIns/AirPortAtheros5424.kext/Contents/Info.plist
and change it to look like (using your own values)
I found my values from booting ubuntu dapper in live mode inside the devices list or whats it called.
Then once again
Remove the Extensions.mkext and .kextcache, make sure you repair permissions so they are correct.
Reboot and open Network, check if Built in is activated (meaning not grayed out, leave it enabled) if so, all is good and there's one last step.
nano /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist and change
reboot and open Network and it should tell you it found the airport card.
DO NOT RUN ANY AIRPORT UPDATES, It will brake dependencies.If you have an Airport Extreme Base Station, use its cd to install Airport Utility BEFORE you install the 10.4.9 update. (I hope you all know you can't install 10.4.9 from Software Update.) Use the different channels to grab it. :-P
After that it worked flawless for me every boot, fully wpa/wpa2.
AND I sold it today with os x installed and bought a Blackbook, nothing todo with this, it just happend today, I have got my eye on macs for long now. Just saying cause I can't check or test anything on it nomore.