I've found a better way than Sean's suggestion. At least it worked out better for me...
As Sean suggests, when XP detects the hardware, don't let it auto-install the drivers, instead choose from specified location.
I went ahead and started with the actual WL200 driver for W2k, after that was installed, I updated the firmware using the utility in the SoftPaq.
Here's the cool part...
Using Sean's suggestion, it seems that you lose the best part of Wireless in XP, the auto-config tools. Well, the WL200 is actually a WL100 soldered to a PCMCIA to PCI adapter. With my particular WL200, XP found the Cirrus PCMCIA fine, so no issues for me there. I decided to try out the WL100 driver from the N600c drivers page (my laptop is an N600c, so I already had that version of the WL100 xp driver handy)
When I asked XP to search the WL100 driver folder, it found 3 drivers:
WL100
PRISM2 PCCard
and ...
PRISM2 PCI Card (the good one)
I choose the PCI Card, and told XP to continue anyway (barked about not being a signed driver)
In less than a minute, it found my wireless network (ad-hoc at the moment)
Overall pretty sweet!