Because I searched for well over a month on how to do just this, I'll add some updates.
This also works for the Dell Vostro A860 (and probably A840) so hopefully this thread will popup for those searching for something other than Acer.
The URLs in the HOWTO are dead, dead, dead. Bad admins for the madwifi project, bad, bad admins It appears they've done some major cleanup and organization on their site(s), but they've left a ton of dead URLs around that don't redirect to the proper places or even at least a page explaining what the heck is going on.
Download madwifi hal driver. I used the one dated 30-Jan-2009 and it worked great. Go here to get a current version URL (as they appear to have gotten rid of the "current" build)
http://snapshots.madwifi-project.org...-hal-0.10.5.6/, then (using the 30-Jan-2009 file as an example:
... and extract it:
Go into source directory:
tar zxvf madwifi-hal-0.10.5.6-r3938-20090130.tar.gz
... and run:
sudo modprobe ath_pci didn't seem to do anything for me on the Vostro A860, I had to actually reboot the computer for the wireless to work. Good news is that the wireless is automatically working on any reboot and you don't have do anything special as I've seen on other HOWTOs.
sudo make install
sudo modprobe ath_pci