Yup, ath9k should be the module and it's been in the kernel since 2.6.27, I believe.
As said, make sure the wireless-tools package is installed.
Check if the module is loading
If that shows nothing try loading it
sudo modprobe ath9k
Check if that now shows the device
Try bring the device up
sudo ifconfig wlan0 up
And last try installing backported wireless modules for Lucid
sudo apt-get install linux-backports-modules-wireless-lucid-generic