If it's a IBM high rate card you can flash the chipset with a newer version of the firmware (not available from IBM). Take a look at
http://linux.junsun.net/intersil-prism/, you'll want the 1.7.4 version. You then need to install a different driver than the IBM one, because it doesn't have the right hooks for windows WPA implementation. I don't remember what it is at the moment, I have to run but I can look it up for you later.
I did this with my T23 and now can use WPA in Windows XP. The only caveat is with the driver I'm using you can't disable the card, so if the wireless connection goes flaky you have to manually disconnect from the AP or restart the computer in order to re-connect. But in general it works OK. Better than being stuck with WEP, which is not much better than transmitting in the clear.
Be aware that flashing your wireless card could kill it, if something went wrong. I was nervous about this at first, but it's not really a big deal, and is worth it for WPA (if you use linux it'll work under there as well, no driver changes needed).
EDIT:
The driver you need can be downloaded from fujitsu
http://support.fujitsupc.com/CS/Portal/ ... =DOWNLOADS
Select the P-Series P2120 laptop, and download the wireless driver. Extract the files, then navigate to the WinXP folder in that directory. You need to replace the prismnds.sys with a newer one, available from
http://www.pretaktovanie.sk/download/in ... ismnds.sys. Then use the XP device manager to update the driver, using the "I will choose the driver to install" and specifying the location of that WinXP folder (from what I recall, the installer does not work). You will get some complaints about driver signing and being unable to determine if it is the right driver for your hardware. Just hit ok, reboot, and it should work.
Yes it's a pain, but worth it if you really want to have WPA in windows with the built in wireless. I should note that the IBM driver won't work with the new firmware (it doesn't recognize the card anymore). You should always be able to downgrade by installing the IBM firmware, but since I never tried it, I can't say for sure; this may be a one way upgrade.