Many times I have come across this thread on forums… many wondering how to get their wifi card (Atheros) to work under Linux (Centos) and then how to proceed to get WPA working… now here is the bundle you have been looking for.
1) Do you have an atheros card?
lspci |grep Atheros (should give you enough info)
2) Get the madiwifi tarball
Go there http://snapshots.madwifi-project.org/madwifi-hal-0.10.5.6/ and download the latest tarball.