I also have a boomslang 2000... and did notice that.. I wrote to them and this is what i got back.. this was before win xp was even out.
"We have done nothing with XP as yet, but our contacts at Microsoft who do the QA all use Boomslangs (they tell me that they prefer them over anything that Microsoft makes, lol), and told me that they built in acceptance to our drivers. So, hopefully you can run XP with your current Razer drivers."
I know there are some problems but they are working on it... I love this mouse and would never give it up!
I have version 2.1.00 by the way...
ASiDiE