先日、下記のWarningが出ていた件ですが
madwifi-0.9.3.1# iwconfig 省略 Warning: Driver for device ath0 has been compiled with version 22 of Wireless Extension, while this program supports up to version 20. Some things may be broken... ath0 IEEE 802.11b ESSID:"" Nickname:"" Mode:Managed Channel:0 Access Point: Not-Associated Bit Rate:0 kb/s Tx-Power:0 dBm Sensitivity=0/3 Retry:off RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality:0 Signal level:0 Noise level:0 Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0
とりあえず、本家のwireless-toolsからversion29-pre22を持ってきて
wireless_tools.29# make wireless_tools.29# make install
とすることで、解決できました。