Look in TurdInc.   I think Matt has a key you can use to activate.  I haven't used XP regularly in 3 years.

If you have XP x64 bit most cracks probably wont work since the x64 edition isn't really based on Windows XP- it's based on Windows 2003.  I honestly don't remember needing an activation crack for XP x64- you get the version with no activation and not the trial edition.