U3b3rcr4ck3r strikes again, eh?
And as for Windows XP. Any Win32-client should work on WinXP. But I would suggest you get LimeWire 1.9 alpha. It now has swarmed downloads and seems to work ok.
I compiled it from cvs and you should be able to access it at
ftp://whitedragon.dyndns.org/lw.zip . I tested it on linux, so I can't give you any guarantee it will even start.