"Microsoft has claimed that it's introduced features in SP2 which mean that illegal users of stolen or cracked activation codes won't be able to upgrade the OS, which is due for release in August of this year.
However, sources in the community are claiming that there's already a keygen for service pack 2 out in the wild that will bypass the security arrangements."
I've certainly just come across something called a "Windows XP SP2 Professional Edition Corporate Reg Code" on one of the serialz sites out there. Please remember that piracy is illegal. Please also remember that downloading anything from a serialz or warez site could land you with a nasty virus.