I just installed kernel 2.6.13.4. The drivers for ipw2200 (1.0.8) and ieee80211 (1.1.6) are loaded and iwconfig shows wlan0. Firmware 2.4 was installed in the appropriate firmware directory. I was using wpa_supplicant-0.3.9 prior to the kernel upgrade. I tried recompiling (no errors) and installing but I still cannot connect to my AP. So I tried upgrading to wpa_supplicant-0.4.5. It compiled & installed OK but running wpa_supplicant still produces:
ioctl[IPW_IOCTL_WPA_SUPPLICANT]: Operation not supported
I'm using WPA-PSK.
If you want me to supply the complete debugging output let me know.
The intel wireless chip associates with the AP with the encryption turned off.