The first step is do determine exactly which interface you have. It is the manufactures identification code of the controller that is important. One linksys network card has used three separate controllers in its history even though the model was the same.
Use the lspci command to get this information.
sudo /sbin/lspci -v | sed -n '/Atheros/,/^$/p'
14:00.0 Network controller: Atheros Communications Inc. Device 002a (rev 01)
Subsystem: Foxconn International, Inc. Device e009
Flags: bus master, fast devsel, latency 0, IRQ 10
Memory at f2100000 (64-bit, non-prefetchable) [size=64K]
Capabilities:  Power Management version 2
Capabilities:  Message Signalled Interrupts: Mask- 64bit- Queue=0/0 Enable-
Capabilities:  Express Legacy Endpoint, MSI 00
Capabilities:  MSI-X: Enable- Mask- TabSize=1
jschiwal@qosmio:~> /sbin/lspci -n | grep '14:00.0'
14:00.0 0280: 168c:002a (rev 01)
I used sed & grep simply to filter the results. Note how the pci address from lscpi -v is used to select the lscpi -n entry.
You will probably need either ath5k or ath9k or madwifi. Check the madwifi web site.
You may have a device that isn't supported yet. In that case, you may need to wait a while before being able to use the latest Wireless-n card.
Originally Posted by madwifi.org
MadWifi has been declared legacy, in response to our commitment to ath5k. In the long run ath5k will replace MadWifi. For the time being MadWifi will still be supported, bugs will get fixed and HAL updates will be applied where possible. But it becomes unlikely that we'll see new features or go through major changes on that codebase.
The driver is mature and stable, though, and works well for most users. For now you should choose MadWifi if you depend on solid WLAN support. But we also encourage all interested users to give ath5k a try.
I think that the ath9k is for wireless-n. It isn't ready yet as far as I know, but might be shortly. When I first got my HP laptop with a broadcom chip, I needed to use ndiswrapper. However I had to wait until a windows 64 bit driver was available (for windows 2003 server).
ath9k - Atheros unveils free Linux driver for its 802.11n devices
We are pleased to announce Atheros has released ath9k to the community. This driver is aimed at inclusion to the Linux kernel and supports all Atheros IEEE 802.11n devices. This represents a major shift in terms of support from Atheros with respect to Linux. The ath9k driver comes shortly after Atheros hired two key Linux wireless developers -- Luis Rodriguez and Jouni Malinen.
We have been informed Atheros does plan to add access point support to ath9k and to work with the community to enhance and complete access point support in the Linux kernel. It is understood there is plenty of work required on the wireless stack to complete full access point support. Jouni Malinen will help drive this process within the community while Luis helps enhance regulatory compliance in the Linux kernel.
We are eager to work with Atheros with ath9k and applaud their efforts for properly supporting Linux.
The ath9k driver includes supports for the following chipsets:
This driver needs a >= 2.6.26 kernel.