I just did an upgrade towards Kubuntu 8.10 on a friend's laptop Toshiba Satellite TK-55 AMD64 Athlonx2 and wireless was not working even though it had an Atheros chipset. The previous madwifi configuration was not working. so I started working and found out that it is possible to make it work with the ubuntu drivers.

Making wireless work with Kubuntu 8.10 is easy. Just follow these steps:

1. Remove linux-backports by coding: 

sudo apt-get remove linux-backports-modules-intrepid-generic

2. Reboot

3. Install or update by coding 

sudo apt-get install linux-backports-modules-intrepid-generic

4. Reboot

5. Open Hardware Drivers and disable “Support for Atheros 802.11 wireless LAN cards” and make sure that “Support for 5xxx series of Atheros 802.11 wireless LAN cards” is enabled. 

6. Reboot

Once you have done these, you will be able to see both drivers active and you will have your wireless working. To check if wireless is ok, just open kNetworkManager. 

In the previous solution we used the Ubuntu drivers. On some laptops such as Acer Aspire 4520, there is another solution that worked for me:

1. disable Atheros in Hardware drivers:

2. reboot

3. sudo apt-get install build-essential

4. wget http://snapshots.madwifi-project.org/madwifi-hal-0.10.5.6-current.tar.gz

5. Extract in your home directory: tar xvf madwifi-hal-0.10.5.6-current.tar.gz

6. Inside the directory code: sudo make sudo make install

7. to load the module code:

sudo modprobe ath_pci

8. Reboot

Everything should now work properly.