Glad to report that thanks to various hints offered in this thread I could get this problem solved in my T43 (with Intel 2200BG)

this forum sure rocks ...
My problem was same as reported by many..I had AC3.81 and it FN+F5 didn't used to show Wireless radio (only BT radio was there), I installed AC4.11a and the latest power management driver (via Software installer) and I started getting Wireless Radio in Fn+F5 but couldn't on/off it from there at all.
Now I did this-
1) Remove wireless adapter from Odyssey and Disabled it.
2) Remove AC4.11 a (keeping the profile) from Software installer
3) reboot
4) remove Wireless LAN adapter s/w for 2200BG using Your uninstaller ! 2006 (it did clean 7 registery keys left over by uninstall program)
5) remove Intel Proset s/w using Your Uninstaller! 2006 (it did clean 7 registery keys left over by uninstall program)
6) Ran Intel's cleanup script, it also found 4 files to delete
7) Reboot and cancel the hardware installation wizard.

Check FN+F5, it was showing only BT radio and was working fine for it.
9) Manually install Wireless driver from C:\ Drivers\1YWC38WW
10) Reboot
11) Check FN+F5, it was now showing Wireless as well as BT radio and was working fine for both.
12) Add wireless adapter from Odyssey and Enabled it and check if able to connect to office wireless LAN -was fine
13) Uncheck "let windows manage wireless option" and see if the Wireless Icon in tray turns green - was fine
14) Manually install AC4.11a from C:\ Drivers\79CN18WW
15) Final Reboot
If you use Odyssey, chances are that like myself you can't use AC to connect to Wireless. In that case remember to uncheck automatic radio control in AC's global settings, else it will keep turning the wireless radio off due to some stupid reason.
thanks to all who helped.